Rotor for fluid pump and method for manufacturing same

Abstract

The present invention provides reinforcement for an impeller element of a rotor for a fluid pump that can assume a compressed state and an expanded state. [Solution] A rotor made of plastic reinforced with reinforcing elements (10, 11, 13, 18, 19) for a compressible fluid pump that can be radially expanded and compressed between a first state, a compressed state, and a second state, an expanded state, wherein the rotor is made by injection molding with the simultaneous addition of reinforcing elements (10, 11, 13, 18, 19) that reinforce one or more impeller elements (15) in the expanded state, and the reinforcing elements (10, 11, 13, 18, 19) are surrounded on all sides by injection-molded material and exist in an at least partially extended form in the expanded state, particularly an extended form to an extent of at least 90%, more particularly 95%, and even more particularly 99%.

Description

[Technical field]

[0001] This patent application is in the field of mechanics and in particular relates to rotors for fluid pumps, which can be used to advantage in the field of medical engineering, especially for catheter pumps. [Background technology]

[0002] In the field of fluid pumps, rotor pumps are already known in various embodiments in the form of axial or radial pumps, in each case the rotation of a rotor and an impeller element fixed to said rotor accelerates the fluid to be conveyed in the axial or radial direction.

[0003] Moreover, such pumps can be compressed according to the prior art, allowing them to be placed or transported in a space-saving manner. This is particularly true for medical catheter pumps, which can be radially compressed, deployed, and often transported to the application site through a catheter or a cavity in the patient's body prior to surgical setup, and then deployed at the application site. Such pumps are used, for example, to assist the patient's heart in circulating blood, and for this purpose are delivered through blood vessels to or within the ventricles of the heart.

[0004] In this case, in addition to the miniaturization of the rotor, its compressibility is a particular issue: in the deployed state, the rotor must assume a reproducible operating form that remains as constant as possible, even when operating at maximum rotational transport speed, despite its compressibility, to prevent loss of efficiency as well as damage to the blood components to be transported.

[0005] For this reason, the use of a wide range of materials and material combinations has already been considered and investigated for the above purposes. As an example, the use of a wide range of elastomers in conjunction with fiber reinforcements is already known from WO 2010 / 063494.

[0006] WO 2012 / 007141 discloses reinforcement of pump rotors with fibers that can be arranged in the rotor, for example, in a radially oriented fashion.

[0007] Finally, WO 2012 / 007140 discloses a pump rotor with strengthening elements which may be provided substantially on the outside (eg on the surface) of the impeller element. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] International Publication No. 2010 / 063494 [Patent Document 2] International Publication No. 2012 / 007141 [Patent Document 3] International Publication No. 2012 / 007140 Summary of the Invention [Problem to be solved by the invention]

[0009] Therefore, against the background of the prior art, it is an object of the present invention to create a plastic rotor of the above type which exhibits minimal slack after deformation between the compressed and deployed states, and which has what is believed to be the most accurate reproducibility of its shape, at least in the deployed state. [Means for solving the problem]

[0010] The above objectives are achieved by a rotor, a method of making the rotor, and a corresponding rotor mold.

[0011] The above results in particular in a rotor for a compressible fluid pump, in particular a blood pump, which can be introduced into a patient's body through a blood vessel, characterized in that it has one or more impeller elements and is radially compressible and deployable between a compressed state and a deployed state, is made at least in part of a plastic reinforced by strand-like reinforcing elements, in particular fibers, is intended to rotate around a rotation axis, and the Shore hardness of the plastic is less than 100D.

[0012] Due to the low Shore hardness, which can be chosen, for example, even below 80D, large curvatures or flexions of the material allow the embedded thread-like reinforcing elements, in particular the fibers, to be forced into the elastic substrate and to limit the radius of curvature downwards, thus reducing the risk of fracture of the reinforcing elements / fibers.

[0013] It is also possible for this type of rotor to be configured such that the first group of reinforcing elements / fibers in the deployed state of the rotor extends substantially elongated from a first end arranged closest to the axis of rotation to a second end arranged further from the axis of rotation. As a result of this positioning, orientation and shaping of the reinforcing elements / fibers, overstretching of the rotor beyond the deployed state is effectively avoided. Here, the term "substantially elongated" can be understood to mean, for example, a state in which the ends of the reinforcing elements have a distance between them of at least 95%, in particular at least 99%, of what is possible without longitudinal extension. The elongated state can also exist only over a portion of the length of the reinforcing elements (for example more than 90% or more than 50% of the length). However, the term "substantially elongated" also characterizes a state of maximum elongation that can be maximally assumed by the fibers of the cross-woven fabric.

[0014] Also provided is a rotor for a compressible fluid pump, in particular a blood pump, which can be introduced into a patient's body through a blood vessel, having one or more impeller elements and which can be radially compressed and deployed between a compressed state and a deployed state, at least partly made of reinforcing elements, in particular plastic reinforced with fibers, intended to rotate about a rotation axis, characterized in that in the deployed state of the rotor a first group of more than 30%, in particular more than 50%, of the reinforcing elements / fibers extends substantially elongated from a first end arranged closest to the rotation axis to a second end arranged remote from the rotation axis.

[0015] The arrangement and orientation of a sufficient amount of reinforcing elements / fibers in such rotors, especially in the impeller elements of the rotor, optimizes the stability of the rotor in the deployed state. The reinforcing elements practically prevent further deformation, or at least ensure a return to the previous rotor shape after overstretching. Thus, certain changes such as material creep of the rotor's constituent plastics do not cause a permanent change in the rotor's shape in the deployed state. This can be achieved, by way of example, by fabricating the rotor using a thermoplastic or a polymer rotor made of thermoplastic or chemically weakly crosslinked elastomers.

[0016] In this case, particularly with regard to the fibers, suitable materials for the strip-shaped reinforcing elements are in particular glass, but also carbon or polycarbonate. For this purpose, the reinforcing elements / fibers are introduced into the polymer in the production process, for example by injection molding or vacuum casting. The individual reinforcing elements / fibers usually have a high elastic modulus and are advantageously incorporated into the matrix in an elongated, non-bent state. In order to stabilize the rotor, a sufficient proportion of reinforcing elements / fibers must fulfil the conditions according to the invention, for example more than 30% of the total reinforcing elements / fibers arranged in the rotor material, as measured based on the mass of the fibers, the volume of the fibers or the mass / volume of the reinforcing elements.

[0017] Thus, according to the invention, it is advantageous to introduce, position and orient at least 50% of a given fiber. It is also possible to configure more than 50% of the reinforcing elements / fibers (for example 60% or 70% or 80% or 90%) to be positioned and oriented accordingly. Here, the maximum possible configuration ratio of the reinforcing elements / fibers can be advantageously arranged in the mid-plane of curvature within the volume of the impeller element of the rotor, so as not to cause longitudinal compression or extension of the reinforcing elements / fibers during compression or deployment. However, a parallel positioning at a certain distance from the mid-plane of curvature may also be desirable for the purpose of achieving a certain stability in a certain direction by elongation of the reinforcing elements / fibers during outward curvature of the impeller element. In any case, the reinforcing elements / fibers advantageously extend over the entire or majority of the impeller element, in particular maintaining a certain minimum distance from the outer boundary surface of the impeller element.

[0018] The rotor may also be provided with a number of groups of reinforcing elements / fibers of different lengths, with at least one group having a certain minimum length, while the reinforcing elements / fibers of one or more groups have a length distribution such that there is a negligible number of reinforcing elements / fibers that are shorter than this or that exceed a length below the nominal length of the first group of reinforcing elements / fibers, the average length of the shorter reinforcing elements / fibers typically being less than one third of the length of the first group of reinforcing elements / fibers.

[0019] Advantageously, the rotor can be designed such that each reinforcing element / fiber of the first group of reinforcing elements / fibers has an axial and / or azimuthal deviation of up to 45° from the radial coincidence with respect to the rotor axis (14). The reinforcing elements / fibers then extend in a plane along which the rotor's axis of rotation extends, so that they can for example extend directly perpendicularly radially outward from the axis of rotation. However, orientation of the reinforcing elements / fibers from the axis of rotation in the radial direction at an angle between 45° and 90° to the axis of rotation is also possible. In one embodiment, the extent of the reinforcing elements / fibers has no azimuthal orientation (extending in the circumferential direction) or only a slight orientation of this kind.

[0020] In another embodiment, the reinforcing elements / fibers of the first group of reinforcing elements / fibers are arranged to extend substantially perpendicular to the axis of rotation, which provides a particularly efficient stabilization when the impeller element is curved circumferentially about the rotor axis and compressed, for example against the rotor hub.

[0021] The radial extension direction of the reinforcing elements / fibers with respect to the axis of rotation is also given simply.

[0022] In another embodiment, each fiber of the first group of reinforcing elements / fibers is configured to extend along the longitudinal axis of the impeller element. This type of arrangement of reinforcing elements / fibers stabilizes the individual impeller elements particularly efficiently in the deployed configuration. Here, it may be advantageous for the reinforcing elements / fibers to extend radially in the areas where the greatest deformations occur during compression and deployment of the rotor. However, it is also possible to arrange the reinforcing elements / fibers in such a way that there are no reinforcing elements or only reduced reinforcing elements in the areas where the greatest deformations occur during compression and deployment of the rotor.

[0023] The longitudinal axis of an impeller element is understood to essentially mean the radial extension of the impeller element with respect to the rotor axis of the rotor, even if the height of the impeller element in the axial direction of the rotor is greater than its radial extent.

[0024] In order to achieve sufficient stability of the rotor or impeller element in the deployed state, it is advantageous for the length of the reinforcing elements / fibers of the first group of reinforcing elements / fibers to be at least 10%, in particular at least 30% and even more advantageously at least 50% of the radius of the rotor, where it is particularly advantageous if the length of the first group of reinforcing elements / fibers is at least 70% of the total length of the given reinforcing elements / fibers, measured based on the number of reinforcing elements / fibers or the mass of the reinforcing elements / fibers.

[0025] In order to avoid the destruction of the reinforcing elements / fibers at the maximum compression of the rotor, the individual reinforcing elements / fibers should not exceed a certain maximum diameter or thickness, especially if they are made of glass. Thus, in one embodiment of the present invention, it is advantageous to configure the reinforcing elements / fibers of the first group of reinforcing elements / fibers to have a diameter or thickness of less than 40 μm. This diameter condition should be met, if possible, for all reinforcing elements / fibers of the first group of reinforcing elements / fibers, but at least for 90% or 80% of the first group of reinforcing elements / fibers, provided that a certain scatter of diameter values ​​during manufacture is unavoidable.

[0026] In order to prevent the reinforcing elements / fibers from being destroyed at the maximum deformation of the rotor (e.g. bending of a certain point of the impeller element), in another advantageous embodiment, by way of example, the plastic in which the reinforcing elements / fibers are embedded can be configured to have a Shore hardness of less than 100 D, in particular less than 80 D. Due to the Shore hardness or elasticity of such a material, the reinforcing elements / fibers in the matrix material can be sufficiently deflected, even in the case of strong deformations, not to fall below a certain curvature radius. In this way, the reinforcing elements / fibers of the first group of reinforcing elements / fibers are protected against destruction.

[0027] The rotor can also be designed in such a way that the impeller elements are made of a foam material. Particularly closed-pore foam materials are considered here, which can be effectively stabilized by the reinforcing elements while still being easily compressible to a sufficient extent. In particular, in the case of foam materials, deflection of the reinforcing elements / fibers during the compression movement is particularly easily possible in order to avoid undershooting of the critical curvature radius. Foam materials of this kind usually have corresponding pores in the volume of the impeller elements, but are in fact completely closed at the external boundary surfaces.

[0028] The invention also relates to a rotor of the above-mentioned kind, as well as to a method for producing a rotor by a molding method, in particular an injection molding method, characterized in that the material of the impeller element is introduced into the volume of the impeller element radially with respect to the rotor axis, such that the injection molding material flows radially into the volume of the impeller element.

[0029] Also, due to the predominant radial flow of the injection molding material into the volume of the mould or impeller element, the reinforcing elements are captured and embedded in the inflow direction, i.e. radially. In this way, the positioning and orientation of the reinforcing elements / fibers in the material of the claimed rotor can be ensured in a particularly simple and effective manner.

[0030] It is also possible to provide that the injection molding material is injected radially into the volume of each impeller element from the area closest to the rotor axis or from the area furthest from the rotor axis.

[0031] The innovation also relates to a mould for a rotor of the above kind, which is advantageously arranged so that the radial edge of the volume of the impeller element is provided with an overflow channel so that the moulding material can flow radially unhindered. By providing the overflow channel at the edge of the impeller element, the reinforcing elements / fibers are not taken up by the mould wall by the swirling of the injection moulding material entering in this area, but are deformed to follow the swirling and are not present in the rotor in an elongated radial orientation. It is also arranged so that the polymer can be partially discharged, but the reinforcing elements / fibers cannot (consequently, the height of the overflow channel is advantageously smaller in at least one spatial direction than the fibre diameter or the thickness of the reinforcing elements). This results in a desired concentration of the reinforcing elements / fibers in the impeller element. The targeted overflow also results in an improved radial orientation of the reinforcing elements / fibers. The overflowed injection moulding material can then be removed from the impeller element once it has solidified. The longitudinal edges of the impeller element are understood to mean the edges of the impeller element which extend substantially in the radial direction of the deployed configuration and which substantially constitute the leading and trailing edges of the impeller element (e.g. an impeller blade) as far as the interaction between the impeller element and the fluid to be conveyed is concerned.

[0032] The rotor can also be formed such that a group of reinforcing elements / fibers in the deployed state of the rotor extends transversely to the first group of reinforcing elements / fibers, in particular including an angle of at least 30° on average. In this way, a specific group of fibers can almost completely prevent curvature of the rotor or impeller element of the rotor in the longitudinal direction of the fibers, provided that the curvature occurs in the direction in which tensile stress is applied to the fibers. If the two directions are thus identified by the different arrangement of the two groups of fibers, the three-dimensional form of the rotor or part of the rotor can be very efficiently stabilized and reinforced against curvatures in various directions.

[0033] It is also possible that at least some of the reinforcing elements / fibers are present in the form of a woven section in which the fibers extend in the longitudinal and transverse directions. By way of example, the woven section can be stretched in the longitudinal direction at least 2, 3, 5 or 10 times as much as in the transverse direction perpendicular thereto, in order to constitute in each case an elongated strip. Then, after a first fiber is easily laid in the longitudinal direction in this woven section, a second fiber extending in the transverse direction is easily laid either perpendicularly or at an obtuse angle.

[0034] It is also possible, by way of example, for the reinforcing elements to be in the form of membrane strips whose length is at least three times, in particular at least five times and more particularly at least ten times, their width. These membrane strips may, for example, consist of anisotropic polymers whose tensile strength in the longitudinal direction is much greater than in the transverse direction. However, they may also consist of isotropic membranes, for example of high-tensile plastic materials or metallic ones, such as aluminum, silver, nitinol, titanium or gold.

[0035] It is also advantageous if the reinforcing elements are configured such that at least 90%, in particular 99%, of their surface, more particularly the entirety, are surrounded by the plastic that constitutes the bulk of the rotor. In individual cases, the reinforcing elements in the injection mould may contact the walls of the mould so that they appear on the outer surface of the rotor in the final product. However, in the usual case, only the ends of the reinforcing elements are arranged exposed on the outside of the rotor, but even this is relatively unlikely due to the introduction of the reinforcing elements during the injection moulding process and the appropriate flow guidance of the injection moulding material.

[0036] It is also possible in the case of rotors that the plastic material in which the reinforcing elements are embedded has different properties at least in the area of ​​the non-flow-pressure side of the impeller element in operation compared to the flow-pressure side of the impeller element, in particular being more bridged or shrunk on the non-flow-pressure side or having supports on the surface that are shrunk on the impeller element, in the form of one or more membranes, coatings or fibres. In this context, the two sides of the impeller element are intended to mean the volumetric areas on the front and rear of the surfaces or surfaces that constitute the curved neutral surface or surface under bending load in the volume of a particular impeller element.

[0037] One of the objects achieved by the invention is that the second state of the rotor assumed by the rotor in the absence of external forces differs minimally from the third state assumed by the rotor in operation, as the rotor rotates in the fluid under the action of the fluid resistance pressure, and therefore the reinforcing fibers already in the second state of the rotor are preferably elongated as much as possible, at least in the direction that delimits the curvature of the rotor.

[0038] This can be assisted in that the shape of the rotor in the second, unloaded state differs from the shape assumed by the rotor in the injection mould. By suitable design of the plastic matrix formed by the injection moulding material, already in the absence of external forces, the elastic forces of the injection moulding material can cause a deformation in the direction of the third state, which preloads the fibres. This effect can be realised, for example, in that a material different from the reinforcing elements is provided in or on the rotor, which brings the rotor, in particular the impeller elements, into a shape in which the reinforcing elements are preloaded. This is realised by modification of the plastic matrix or the rotor body as a whole after completion of the injection moulding process, since in the actual moulding of the reinforcing elements in the matrix, practically no force is applied to these elements. As an example, the plastic matrix can be specially treated after removal from the injection mould, so that the material of the impeller elements is elongated on the side where the fluid resistance pressure is applied during operation, or contracted or anisotropically shortened on the opposite side. This is realised, for example, by irregular bridging of different plastic matrices on the two sides of the neutral fibres of the impeller elements. However, this can also be achieved by coating the impeller element on the side opposite the side exposed to the flow resistance pressure during operation with a film that shrinks after coating or can be shrinkable, for example by electron beam or UV crosslinking or heat treatment.

[0039] It is also possible to provide a rotor for a compressible fluid pump that is radially expandable and compressible between a first state, a compressed state, and a second state, a deployed state, in which one or more impeller elements of the rotor are made by injection molding with the simultaneous addition of reinforcing elements that provide reinforcement in the deployed state, the reinforcing elements being surrounded on all sides by the injection-molded material and at least partially elongated in the deployed state, in particular elongated to an extent of at least 90%, more particularly 95%, even more particularly 99%, or configured to elongate to the greatest extent possible through the use of textiles.

[0040] Also, by way of example, the rotor can be designed such that the reinforcing elements in the rotor's second state, i.e. the deployed state, in which there is no fluid resistance pressure, elongate by less than 5%, in particular less than 1%, upon transition to a third state constituting an operating state in which there is fluid resistance pressure, said elongation being measured in particular based on the distance between the two ends of the reinforcing elements before and during tensile loading.

[0041] Also, by way of example, in the case of a rotor, in a second state of the rotor, the deployed state, and / or in a third state of the rotor, the operating state, with a fluid resistance pressure, it is possible to configure at least a group of the reinforcing elements, in particular at least 10%, more particularly at least 30%, to be elongated and extend straight in at least one curved region of the impeller element.

[0042] It is also possible to configure at least two groups of reinforcing elements in the curved region of the impeller element so that they extend in a straight line and the directions of extension of the reinforcing elements are parallel within the same group but different between said two different groups. The fibres in the various groups can be introduced into the injection mould either connected to one another in the form of a fabric or separate from one another, in particular continuous.

[0043] In another embodiment of the rotor, it is also possible to configure that the length of at least 30%, in particular at least 50%, of the reinforcing elements is greater than the average thickness of the impeller element, in particular at least twice as long, more particularly at least 5 or 10 times as long. Reinforcing elements of such length can be supplemented by other filling elements (for example very short fibers and / or particles) during filling of the molding material, which short fibers can also be present in elongated form. However, since these fibers are usually very short, they have little effect with regard to the limits of curvature of the rotor. In this context, the thickness of the impeller element at any point of the impeller element means the dimension in the direction in which the dimension of the impeller element is smallest.

[0044] In another embodiment of the rotor, it is also possible for the reinforcing elements, in particular the fibres, to be introduced into the embedded plastic during injection moulding and, when the rotor is placed in the injection mould, to have a direction of extension that is partially curved along the flow of the plastic into the injection mould.

[0045] The invention also relates to an injection mould for a rotor of the above kind, in which the radially extending edges of the volumes of the impeller elements are provided with overflow channels so that the moulding material can flow unhindered in the radial direction.

[0046] In the method for producing the rotor, it is also possible to configure the material of the impeller elements to be introduced into the volumes of the impeller elements radially with respect to the rotor axis, such that the molding material flows radially into the volumes of the individual impeller elements.

[0047] By the placement and size of the overflow channels in the mold, the flow direction of the incoming molding material and therefore the orientation of the fibers along the flow can be controlled.

[0048] In another way of producing the rotor, it is possible to arrange for the rotor to be produced by moulding, in particular by injection moulding, the injection moulding process being carried out in two successive stages with different injection directions and / or from two different injection points, so that reinforcing elements / fibers running in groups in different directions can be introduced into the injection moulding material in a targeted manner.

[0049] It is also possible in the method of making the rotor to be configured such that, after injection molding, the rotor is subjected to a treatment in which the molding material on the side of the impeller element that is subjected to the drag pressure during operation shrinks and / or crosslinks differently from the other side. Thus, the rotor can be preloaded by the creation of internal stresses so that, when exposed to the drag pressure, it assumes a third state, i.e. a working state, which is stable without the influence of external forces. This is realized in that the internal stresses are directed and created so that tensile forces, which exist in the order of forces to which the reinforcing fibers are exposed during the operation of the rotor, are applied to the reinforcing elements as a result.

[0050] Also, by way of example, a shrinkable or contractible layer may be applied to at least one of the impeller elements opposite the side of the impeller element exposed to the flow resistance pressure during operation.

[0051] Alternatively or additionally, it is also possible, by way of example, to configure the injection mould for the injection moulding material such that it is provided with at least two different injection openings, so that the flow of the injection moulding material in the mould can be modified in a targeted manner during the moulding process by the addition of reinforcing elements at different stages, in each case such that the reinforcing elements can be arranged in different directions relative to the main flow direction of the injection moulding material, according to the different stages of the injection moulding process.

[0052] For this purpose, by way of example, first and second quantities of injection molding material can be injected through the first and second injection openings, respectively, either sequentially or simultaneously or in variable proportions to one another.

[0053] The innovation is presented and explained below on the basis of exemplary embodiments in the drawings. [Brief description of the drawings]

[0054] [Figure 1] FIG. 1 is a schematic cross-sectional view of a catheter pump introduced into a patient's ventricle. [Figure 2a]FIG. 2 is a detailed view of the rotor of a catheter pump that transports blood. [Figure 2b] FIG. 2 is a cross-sectional view of a spreading rotor with a fiber shown as an example. [Diagram 3] FIG. 2 is a schematic diagram of a plane including the rotation axis of a rotor. [Figure 4] FIG. 13 shows a detail of a planar impeller element with reinforcing fibers. [Figure 5a] FIG. 1 illustrates the orientation of fibers during the molding process. [Figure 5b] FIG. 5 is a side view of a portion of FIG. [Figure 6] FIG. 6 shows the portion of the impeller element shown in FIGS. 4 and 5 after the bending process. [Figure 7] FIG. 2 is a schematic diagram of a forming tool for a rotor with flow arrows indicating the forming process. [Figure 8] FIG. 8 shows a mold for a rotor in which the injection direction is opposite to that in FIG. 7. [Figure 9] FIG. 1 shows a mold in which measures are taken to prevent swirling of the injection molding material in the volume of the impeller element. [Figure 10] FIG. 13 is a diagram showing another mold. [Figure 11] FIG. 2 shows a membrane strip-shaped reinforcing element. [Figure 12] FIG. 1 shows a woven strip-like reinforcing element. [Figure 13] FIG. 2 is a cross-sectional view of an impeller element. [Figure 14a] FIG. 2 shows a woven fabric made of fibers in an unstressed state. [Figure 14b] FIG. 14b shows the fabric of FIG. 14a maximally stretched under load. [Figure 15a] FIG. 2 is a perspective view of the impeller element in an unfolded state without the action of an external force. [Figure 15b] FIG. 15b is a cross-sectional view of the impeller element taken along line AA of FIG. 15a. [Figure 16a] FIG. 2 is a perspective view of the impeller element in an unfolded state without the action of an external force. [Figure 16b]FIG. 16b is a cross-sectional view of the impeller element taken along line BB of FIG. 16a. [Figure 17a] FIG. 2 is a side view of the impeller element in a deployed state without the action of an external force. [Figure 17b] 17b is a cross-sectional view of the impeller element taken along line CC of FIG. 17a. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0055] 1 shows a cross-section of a patient's heart 1 having multiple chambers, with the ventricles 2 connected to an aorta 12. A catheter 4 is advanced through the aorta 12 to the ventricle 2, at the end of which a pump head 3 with a rotary pump is disposed. The rotary pump is drivable by a rotatable shaft 6 which extends through the catheter 4 and is connected to a pump rotor 42 within the pump head 3. The pump rotor rotates in a housing of the pump head 3 (not shown in further detail).

[0056] The flexible shaft 6 is connected to a motor 7, which is arranged, for example, outside the patient's body. Torque can be transmitted from the motor 7 to the shaft 6 in both rotational directions 8, 9, for example by magnetic coupling.

[0057] Catheter 4 is typically advanced from outside the body, through a port, through the skin and tissue, as well as the blood vessel walls, into and within aorta 12.

[0058] The pump draws blood from the ventricle 2 and delivers it to the aorta 12. In this way, the heart pump is able to assist or at least temporarily replace the function of the heart 1.

[0059] In addition to the mechanically driven catheter pump shown, other pumps, particularly for internal use, such as hydraulically or electrically driven pumps, including pumps driven within the human body, also form the subject of this patent.

[0060] The pump, together with the pump head, pump housing and rotor, is radially compressed for displacement in the artery, for example within the catheter 4. The pump can then be axially slid out of the catheter 4 and radially unfolded or deployed. This process places high demands on the material of the pump housing and in particular the pump rotor, whose impeller element must have a very thin wall thickness but be dimensionally stable to transport blood reproducibly, even at high rotational speeds.

[0061] For this purpose, reinforcing fibres (fibers) are embedded in the plastic matrix of which the rotor is made, and may be provided, for example, as glass fibres or polycarbonate fibres. Such reinforcing elements / fibres are illustrated in three separate examples in Fig. 2a. Three reinforcing elements / fibres 10, 11, 13 are shown, each having a first end or first portion 10a, 11a, 13a that is closer to the axis of rotation 14 than the second ends / second portions 10b, 11b, 13b of said reinforcing elements / fibres 10, 11, 13.

[0062] The reinforcing elements / fibers 10, 11, 13 extend substantially radially outward from the rotor's axis of rotation 14 or a point near the axis of rotation, where the rotor 42 need not have a hub 43 as in the illustrated example, and the helical impeller element 15 may have inherent stability such that a rotor hub is not required.

[0063] In principle, the plastic matrix of one or more impeller elements 15 can be reinforced by reinforcing elements / fibers randomly distributed and arranged with respect to length and / or thickness and / or orientation. In one embodiment, a certain minimum group of reinforcing elements / fibers in the deployed state of the rotor shown in FIG. 2 extends substantially elongated away from the axis of rotation. Of the total number of reinforcing elements / fibers embedded in the plastic of the rotor, the group of reinforcing elements / fibers that fulfill the above conditions should be at least 30%, advantageously 50%, more advantageously, for example 70%, based on a percentage measurement by volume or mass of the reinforcing elements / fibers or on the number of reinforcing elements / fibers. Advantageously, here, a certain minimum length of the reinforcing elements / fibers is given, for example at least about 20%, at least 40% or even 50% of the radius of the rotor. The reinforcing elements / fibers can easily change from an axial orientation corresponding to the hub 43 to a radial position of the impeller element 15 without bending when filling the mold. This is due to the relatively flat extension of the impeller element 15 and the hub 43, with an angle of less than 30°, preferably less than 20°. Thus, the reinforcing elements / fibers are easily taken up by the surrounding matrix during radial filling of the impeller element 15 and are radially oriented by the material flow in the impeller element according to FIG.

[0064] Another advantageous property of the reinforcing elements / fibers is their specific maximum thickness, which may be advantageously a diameter of up to 40 μm, so that the reinforcing elements / fibers do not break even in the case of strong bending of said reinforcing elements / fibers. In contrast, at a size of about 40 μm, the reinforcing elements / fibers are sufficiently flexurally rigid to return the surrounding matrix to its initial state after deformation and to prevent long-term creep of the matrix under permanent bending loads. Furthermore, reinforcing elements / fibers with a diameter of 40 μm exhibit resistance to compressive and tensile stresses, and, due to their placement outside the neutral bending region, generate restoring moments and resist other deformations.

[0065] The reinforcing elements / fibers can be coated with an adhesion promoter to improve their connection to the matrix.

[0066] Figure 2b shows a cross section of the rotor 42' with the impeller elements 15', 15'' in a stretched, deployed state. In this state the reinforcing elements / fibres 55, 56 are in their maximally elongated configuration and therefore resist further deformation of the rotor due to their longitudinal stiffness.

[0067] A possible orientation of the reinforcing elements / fibers is explained in more detail with reference to figure 3. In figure 3, the rotor hub is designated 16 and the axis of rotation is designated 14. A plane 17 based on a cutting rectangle is shown, which plane 17 includes the axis of rotation 14, i.e. the axis of rotation 14 extends completely within the plane 17.

[0068] By way of example, two reinforcing elements / fibers 18, 19 are shown, both of which extend substantially radially in the plane 17 with respect to the axis of rotation 14. The fibers 18 extend at an angle α to the axis of rotation 14 and have an axial component, which angle α is conveniently between 45° and 90°. The fibers 19 are oriented so as to be disposed perpendicular to the axis of rotation 14. Real braids are curved in a three-dimensional helix, which often limits the extent of the reinforcing elements / fibers in the azimuthal direction.

[0069] The individual reinforcing elements / fibers need not be positioned such that their initial start / end points are within the region of the rotational axis 14 or rotor hub 16. Also, the individual reinforcing elements / fibers can be positioned to extend between two end points radially away from the rotor axis 14 and / or rotor hub 16. However, in any case beyond the axis, the individual reinforcing elements / fibers can extend from a first radially outer blade edge to a second radially opposite blade edge.

[0070] A detail 20 of an impeller element is shown diagrammatically in figure 4, this detail 20 being cubic in shape. In the part 20 the fibres 19 are shown.

[0071] Figure 5a clearly shows how a central orientation of the fibres 19 is achieved. The preferably laminar flow profile when filling the mould between the boundary walls 53 and 54 has the highest flow velocity in the centre and the lowest flow velocity close to the walls. The initially inclined fibres 19 are shown in three angular positions reached successively from left to right and are drawn towards the centre of the flow profile by the material flow indicated by arrows 50, 51 as a result of the velocity distribution in the mould. The velocity distribution of the flow is shown in the graph 52 in the figure with axes x (velocity) and y (position coordinate in the mould).

[0072] FIG. 5b is a side view showing a see-through material of portion 20 so that the direction of extension of fibers 19 approximately midway between the boundaries of the impeller elements is visible.

[0073] The behavior of the fibers under large curvature or bending of the impeller element will now be described based on FIG.

[0074] Figure 6 shows a part 20 of the impeller element after bending. The fibres 19 are also deformed. However, due to the specific inherent stiffness of the fibres, in the case of bending, the elasticity of the material of the impeller element allows them to protrude outwards in the direction of the arrow 21, so that the maximum possible radius of curvature of the fibres is achieved and the fibres are prevented from breaking. In the region of the bending point, the fibres 19 therefore deviate from the centre between the boundary walls of the impeller element during bending. In Figure 6, for clarity, at least a part of the central surface of the impeller element is shown by a dotted line 22. To achieve this effect, the flexibility of the plastic matrix of the rotor is favoured, which corresponds to a Shore hardness of less than 100D.

[0075] In the following, the inventive design of a forming tool / mold for a rotor according to the invention will be discussed based on FIG.

[0076] FIG. 7 shows a longitudinal section of an injection mould with an area containing the rotor hub volume at 23 and the individual impeller element volumes at 24, 25, 26 and 27. Also in FIG. 7, the injection direction is shown by arrow 28. The other arrows 29, 30, 31, 32, 33 show that the injection moulding material flows axially along the axis of rotation 14 of the final rotor and from there radially outwards into the impeller element volumes. By way of example, the longitudinal axis of one of the impeller elements is shown by dashed and dotted line 44. If a sufficient number of reinforcing elements / fibers of suitable length are introduced into the injection moulding material, they will orient themselves according to the main flow direction of the material and will remain so upon solidification of the material.

[0077] The displaced air and excess molding material are allowed to exit through openings 45 at the radially outer ends of the impeller elements.

[0078] 8 shows the opposite injection direction, where the injection molding material is injected radially inwards from the radially outer ends 34, 35 of the impeller elements into the volume of the rotor 23. Again, long reinforcing elements / fibers can be introduced, oriented and positioned as intended according to the present invention.

[0079] Based on FIG. 9, it can be shown that in the case of narrow impeller elements 36, 37, the molding material flowing radially from the inside does not flow laminarly because it swirls due to friction at the edges 38, 39 of the volume of the particular impeller element.

[0080] The left side of FIG. 9 shows a variant of the mold with overflow openings or overflow slots in the region of the edges 40, 41, through which part of the injection molding material can flow out in the axial direction of the rotor, thus eliminating the swirling shown on the right side of FIG. 9. In the central region of the impeller element 37, a pseudolaminar flow is thus created, so that the introduced reinforcing elements / fibers can themselves assume an elongated form without deformation under the influence of the flow of the injection molding material. When the injection molding material solidifies, the part that can exit from the openings at the edges 40, 41 of the volume of the impeller element in the injection mold is removed, for example by cutting. The situation can be the same at the outer edge of the impeller element, as in FIG. 7. Here, an overflow channel 45 is provided through which the plastic without the reinforcing elements / fibers can leak out.

[0081] FIG. 10 shows a schematic of an injection mould 70 with a first injection opening 71 and a second injection opening 72, which are located at opposite ends of a central cavity 73 in which the hub of the rotor is formed in the moulding process. The cavities in which the impeller elements are formed are shown very diagrammatically and are indicated at 74 and 75. The arrows 76, 77 indicate the flow direction of the plastic entering the mould. If the plastic is injected into the mould from the first injection opening 71 and the second injection opening 72 in succession or at alternating rates, different flow directions of the liquid moulding material are formed. If reinforcing elements are added to this, the reinforcing elements will also have different orientations in the produced rotor. Thus, different orientation patterns can be obtained in the moulding process by controlling the injection speed through the injection openings and by varying the injection speed or the ratio of injection speeds through the various injection openings.

[0082] A perspective view of a reinforcing element in the form of a metal foil or plastic film 78 is shown in FIG. 11, which foil / film may, by way of example, be only a few micrometers thick, a few tenths of a millimeter wide and a few millimeters long.

[0083] 12 shows an elongated textile strip as a reinforcing element, which has, diagrammatically, only two longitudinally extending fibres 79, 80 and a number of transversely extending short fibres 81. A textile of this kind is able to fully absorb tensile forces in both longitudinal directions of the fibres present.

[0084] 13 is a schematic cross-sectional view of an area of ​​an impeller element 82, where 83 denotes the cover surface that is on the pressure side during operation and is exposed to the fluid resistance pressure indicated by arrows 84.

[0085] The opposite side or covering surface to covering surface 83 is designated 85. In the illustrated example, this side of impeller element 82 is provided with a coating 86, which may be provided by an adhesive film or a liquid coating (e.g. varnishing).

[0086] Also shown is dashed line 87, which is known in the mechanical sense as the neutral "fiber" or plane for the curvature of impeller element 82 during pump operation.

[0087] If the impeller element shown in FIG. 13 is considered to be in a no-stress state, i.e., a state in which no external force is acting on the impeller element, then in this state, it is also possible to configure the reinforcing element, as shown by way of example at 88, to exist in an extended form with no force applied thereto.

[0088] When a bending force in the direction of arrow 84 acts on the impeller element due to the action of fluid resistance pressure 84 during rotation of the rotor in the fluid, the neutral fibers 87 arranged on the left side of the figure become longer as a result of bending of the impeller element, so that the reinforcing elements 88 are subjected to a tensile load. Since the reinforcing elements 88 actually resist elongation, they limit the bending.

[0089] In order to further reduce the difference in the rotor geometry between the second unloaded state and the third or loaded state, it is also possible to configure the reinforcing elements 88 to be pre-stressed with internal material stresses in the unloaded state, i.e. when no external forces act on the rotor, in that the impeller elements are stretched on the cover surface 83 side or contracted on the cover surface 85 side after the rotor is fabricated, more particularly after the injection molding process is completed.

[0090] This is realised, for example, in that a coating 86 is applied to the cover surface 85 after or during the injection moulding process, for example by impregnation of the injection mould, which coating may be shrunk during drying or crosslinking or by subsequent treatment, in particular by electron beam crosslinking, UV crosslinking or heat treatment, and electron beam crosslinking may also be introduced, for example, by one or more laser beams, and therefore may be applied locally in a very focused manner.

[0091] However, in addition to or as an alternative to the cover layer 86, it is also contemplated that the material of the impeller element 82 on the neutral plane side of the fibers 87 facing the cover layer 85 may be shrunk, for example by heat treatment or crosslinking / polymerization that does not occur or only to a small extent occurs on the other side of the impeller element.

[0092] 14a and 14b show, by way of example, a woven fabric made of fibres, where fibres 90, as part of fibre bundles, extend at an angle to other fibre bundles 91, but the fibre bundles 91 are arranged perpendicular to the plane of the drawing and the fibres 90 pass through the fibre bundles 91 alternately from left to right. In FIG. 14a, which represents the deployed state of the rotor, the fibre bundles 91 are arranged at a distance a from each other and the fibres 90 have a curved extension direction back and forth. In FIG. 14b, which represents the state of the rotor in operation, the fibre bundles 91 are arranged at a greater mutual distance a' and the fibres 90 have a less curved extension direction. From FIG. 14a and 14b it is clear that this type of system reaches a substantially stable state before the fibres 90 are fully extended. After the state of FIG. 14b, the fibre bundles 91 would need to move perpendicular to the fibres 90 in the substrate, but this is essentially prevented by the fibre bundles 91 and the fibres 90.

[0093] FIG. 15a shows a perspective view of the rotor in an unloaded deployed state, also showing the cross section AA. FIG. 15b shows a cross section of the same rotor along said cross section. The dotted lines 101 and 102 represent the neutral fibers or surfaces of each blade. The fibers 103 and 104 show, by way of example, the extension direction of the two fibers in the planar cross section shown. The fibers are curved in this state. In the operating state under load, the fluid exerts a pressure on the blade in the direction of the arrows shown, which causes said blade to be further deployed. Under full operating load, the fibers 103 and 104, respectively, are elongated at least in the areas shown by 105 and 106, preventing further deployment of the blade. This is because the fibers, which are under very high tension, must be further elongated in the axial direction. The advantage of such a design is that above a minimum rotational speed, the blade morphology is virtually constant.

[0094] Fig. 16a shows a perspective view of the rotor in an unloaded state without forces, also showing the cross section BB. Fig. 16b shows a cross section of the same rotor along said cross section. The dotted lines 111 and 112 represent the neutral fibres or surfaces of each blade. The fibres 113 and 114 show, by way of example, the extension direction of two fibres in the cross section shown. As can be seen, the fibres in this example are already maximally elongated. There is little possibility of them becoming any longer, since they are under very high tension. Such blades do not deform much further under the forces shown by the arrows in Fig. 16b, which arise in operating conditions and act on the blades due to the flow pressure, and this has the advantage that the blade shape remains virtually unchanged over the entire range of rotational speeds.

[0095] Fig. 17a shows a side view of the rotor in the unforced deployed state, also showing the cross section CC. Fig. 17b shows a cross section of the same rotor along said cross section. The dotted lines 121 and 122 represent the neutral fibres or surfaces of each blade. The fibres 123 and 124 show, by way of example, the extension directions of two fibres in the cross section shown. As can be seen, the fibres in this example are already elongated over a large area. There is little possibility of them becoming any longer, since they are under very high tension. Such blades do not deform much further under the forces shown by the arrows in Fig. 17b, which arise in operating conditions and act on the blades due to the flow pressure.

[0096] As a result of the above mentioned features, in particular as a result of the rotor design and the introduction of suitable reinforcing elements / fibers, a stable design of the rotor is achieved, the geometry of which is sufficiently accurate even after partial overstretching or frequent load switching or constant application of bending loads.As a result of the manufacturing method according to the invention and the presented injection mould, a convenient and advantageous possibility for manufacturing the rotor according to the invention has been demonstrated.

[0097] The present invention also encompasses the following aspects, each of which may be protected individually, separately and independently:

[0098] 1st aspect: a rotor for a compressible fluid pump, in particular a blood pump, which can be introduced into a patient's body through a blood vessel, comprising one or more impeller elements (15) and which can be radially compressed and expanded between a first state, compressed, and a second state, radially expanded, at least in part made of strand-like reinforcing elements, in particular plastic reinforced with fibers, intended to rotate about an axis of rotation, characterized in that in the first state, i.e. compressed, it is in tension, in the second state, i.e. expanded, it is free of external stresses, and there exists a third state which the rotor (42) assumes in its operating state under load, the various materials of the rotor and their distribution being adapted to one another in such a way that in the second state of the rotor, material stresses are selectively generated which cause tension and / or elongation of the reinforcing elements.

[0099] Second aspect: A rotor according to the first aspect, characterized in that the reinforcing element is further configured to be surrounded by plastic of which the majority of the rotor, at least 90%, in particular 99%, of the surface, more particularly the entire rotor, is composed.

[0100] Aspect 3: A rotor according to aspect 1 or aspect 2, characterized in that the plastic material in which the reinforcing elements are embedded has different properties at least in the region of the non-fluid resistance pressure side of the impeller element during operation, in particular in the region of the corresponding side of the impeller element with respect to the fibres or surfaces which constitute a curved neutral fibre or a plane during pump operation under bending load, compared to the fluid resistance pressure side of the impeller element, in particular being more bridged or shrunk on the non-fluid resistance pressure side or being further configured to have supports on the surface thereof, in the form of one or more membranes, coatings or fibres, which supports are provided.

[0101] Fourth aspect: A rotor according to the first, second or third aspect, characterized in that one or more impeller elements of the rotor are made by injection molding with simultaneous addition of reinforcing elements in the deployed state, the reinforcing elements being surrounded on all sides by the injection molding material and present in the deployed state in at least a partially elongated form, in particular to an extent of at least 90%, more particularly 95%, even more particularly 99%.

[0102] Aspect 5: A rotor according to aspect 1, 2, 3 or 4, further characterized in that the reinforcing elements in a deployed state, which is a second state of the rotor in which there is no fluid resistance pressure, are present in an elongated form to an extent that they become longer by less than 5%, in particular less than 1%, upon transition to a third state constituting an operating state in which there is fluid resistance pressure, the elongation being measured in particular based on the distance between the two ends of the reinforcing elements.

[0103] Aspect 6: A rotor according to aspect 1, 2, 3, 4 or 5, further characterized in that in a second state of the rotor, a deployed state, and / or in a third state of operation with a fluid resistance pressure, at least a group of the reinforcing elements, in particular at least 10%, more particularly at least 30%, are configured to extend straight in at least one curved region of the impeller element.

[0104] Seventh aspect: A method of making a rotor for a fluid pump, in particular as described in the first aspect, characterized in that after injection moulding, the rotor is adapted to undergo a treatment which results in different shrinkage and / or cross-linking of the moulding material on the fluid resistance pressure acting side of the impeller element during operation compared to the opposite side.

[0105] 8th aspect: A method for making a rotor for a fluid pump, in particular as described in the first aspect, by injection molding, characterized in that a shrinkable layer is applied to at least one of the impeller elements opposite the fluid resistance pressure exposed side of the impeller element during operation.

[0106] 9th aspect: A mold for a rotor for a fluid pump having an impeller element according to the first aspect, characterized in that the mold is provided with at least two different injection openings.

[0107] 10th aspect: A rotor according to any one of the above aspects, characterized in that the reinforcing elements are configured to have a two-dimensional extent and are, for example, embodied as membrane pieces or fabrics in which groups of fibers cross each other (see Figures 14a and 14b).

[0108] <Additional Notes> [1] A rotor for a compressible fluid pump, the rotor having one or more impeller elements (15) and radially compressible and expandable between a compressed state and an expanded state, made of plastic reinforced at least in part by strand-like reinforcing elements (10, 11, 13, 18, 19), the rotor intended to rotate about a rotation axis (14), The plastic has a Shore hardness of less than 80D, and when the rotor is compressed and the impeller element (15) is bent, the reinforcing element located on the central plane of the impeller element (15) can bend and protrude outward from the central plane of the bent portion, thereby realizing a maximum radius of curvature of the reinforcing element and preventing the reinforcing element from being broken. [2] The rotor according to [1] above, characterized in that a first group of more than 30% of the reinforcing elements (10, 11, 13, 18, 19) in the deployed state of the rotor (42) extends substantially elongated from a portion (10a, 11a, 13a) disposed closest to the axis of rotation to a second portion (10b, 11b, 13b) disposed further from the axis of rotation. [3] The rotor according to [2] above, characterized in that in the deployed state, each of the reinforcing elements (10, 11, 13, 18, 19) of the first group has an extension direction that deviates from a radially coincident position with respect to the rotor axis by up to 45° in the axial and / or azimuth directions. [4] The rotor according to [2] or [3] above, characterized in that in the deployed state, each of the reinforcing elements (10, 11, 13, 18, 19) of the first group extends substantially perpendicular to the axis of rotation. [5] The rotor according to any one of the above [2] to [4], characterized in that in the deployed state, each of the reinforcing elements of the first group extends radially with respect to the rotation axis (14). [6] The rotor according to any one of the above [2] to [5], characterized in that each of the reinforcing elements (10, 11, 13, 18, 19) of the first group extends along a longitudinal axis (44) of the impeller element. [7] The rotor according to any one of the above [2] to [6], characterized in that the length of the reinforcing elements (10, 11, 13, 18, 19) of the first group is at least 10% of the radius of the rotor. [8] The rotor according to any one of the above [2] to [7], characterized in that the diameter of the reinforcing elements (10, 11, 13, 18, 19) of the first group is less than 40 μm. [9] The rotor according to any one of the above items [1] to [8], wherein the impeller element (15) is made of a foamed material.

[10] A rotor as described in any one of [2] to [8] above, characterized in that a group of the reinforcing elements in the deployed state of the rotor extends transversely to the reinforcing elements of the first group.

[11] A rotor according to any one of the above [1] to

[10] , characterized in that at least a portion of the reinforcing elements are present in the form of a woven portion extending in the longitudinal and lateral directions.

[12] A rotor according to any one of the above [1] to

[10] , characterized in that the reinforcing elements are present in the form of membrane strips whose length is at least three times their width.

[13] A rotor according to the above [1] or [2], characterized in that the reinforcing element has at least 90% of its surface surrounded by plastic that constitutes the majority of the rotor.

[14] A rotor according to any one of the above [1] to

[13] , characterized in that the plastic material in which the reinforcing elements are embedded has different properties at least in the region of the non-fluid resistance pressure side of the impeller element during operation compared to the fluid resistance pressure side of the impeller element, and is bridged or shrunk more on the non-fluid resistance pressure side, or has a support portion (86) on a surface of the impeller element (82) that is shrunk, the support portion (86) being provided in the form of one or more membranes, coatings or fibers.

[15] 1. A rotor for a compressible fluid pump, radially expandable and compressible between a first state, a compressed state, and a second state, an expanded state, wherein one or more impeller elements of the rotor are made by injection molding with simultaneous addition of reinforcing elements which reinforce the rotor in the expanded state, the reinforcing elements being surrounded on all sides by injection molding material and present in at least a partially extended form in the expanded state, the reinforcing elements being introduced by injection molding into a plastic in which they are embedded, and which, when the rotor is placed in the injection mold, have a direction of extension which is partially curved along the flow of the plastic into the injection mold.

[16] A rotor as described in any one of the above [1] to

[15] , characterized in that the reinforcing elements in the deployed state, which is a second state of the rotor in which there is no fluid resistance pressure, are present in a form that extends to a length that is less than 5% longer when transitioning to a third state that constitutes an operating state in which there is fluid resistance pressure.

[17] The rotor according to any one of the above [1] to

[16] , characterized in that in a deployed state which is a second state of the rotor and / or in an operating state which is a third state with a fluid resistance pressure, at least a certain group of the reinforcing elements are elongated and extend straight in at least one curved region of the impeller element.

[18] The rotor according to

[17] above, characterized in that in the curved region of the impeller element, at least two groups of reinforcing elements extend elongated and straight, the extension directions of the reinforcing elements of the groups being parallel within the same group but different between the two different groups.

[19] A rotor according to any one of the above [1] to

[18] , characterized in that in at least 30% of cases, the length of the reinforcing elements is greater than the average thickness of the impeller element.

[20] A rotor according to any one of the above items [1] to

[14] , characterized in that the reinforcing elements are introduced into the plastic to be embedded by injection molding, and when the rotor is placed in an injection molding die, the reinforcing elements have an extension direction that is partially curved along the flow of the plastic into the injection molding die. [twenty one] A method for producing a rotor (42) according to any one of the above items [1] to

[20] by injection molding, characterized in that the injection molding material of the impeller element (15) is introduced into the volume of the impeller element in a radial direction with respect to a rotor axis (14) such that the injection molding material flows into the volume of the impeller element in a radial direction (30, 31, 32, 33). [twenty two] The method according to

[21] above, characterized in that the injection molding material is injected into the volume of the impeller element (15) in a radial direction (30, 31, 32, 33) from the area disposed closest to the rotor axis or from the area disposed furthest from the rotor axis. [twenty three] A method for producing a rotor according to any one of the above items [1] to

[20] , characterized in that the rotor is produced by an injection molding process, the injection molding process being carried out in two successive stages with different injection directions and / or from two different injection points. [twenty four] The method according to any one of the above items

[21] to

[23] , characterized in that after the injection molding, the rotor is subjected to a treatment in which the molding material on the fluid resistance pressure side of the impeller element during operation shrinks and / or crosslinks differently from the opposite side. [twenty five] The method according to any one of the above

[21] to

[24] , characterized in that a shrinkable layer is applied to at least one of the impeller elements opposite a side of the impeller element exposed to a flow resistance pressure during operation.

[26] An injection molding die for a rotor (42) according to any one of the above [1] to

[20] , characterized in that overflow channels are provided at the radial edges (40, 41) of the volume of the impeller element (15) so that the injection molding material can flow radially unhindered.

[27] A mold for the rotor according to any one of the above items [1] to

[20] , characterized by having at least two different injection openings.

[28] A rotor for a compressible fluid pump, in particular a blood pump, introduceable into a patient's body through a blood vessel, comprising one or more impeller elements (15) and radially compressible and expandable between a compressed state and an expanded state, made of plastic at least in part reinforced by strand-like reinforcing elements (10, 11, 13, 18, 19), intended to rotate about a rotation axis (14), wherein a first group of more than 30%, in particular more than 50%, of said reinforcing elements (10, 11, 13, 18, 19) in the expanded state of said rotor (42) extend substantially elongated from a portion (10a, 11a, 13a) arranged closest to said axis of rotation to a second portion (10b, 11b, 13b) arranged further from said axis of rotation, said first group of reinforcing elements having a height, measured in the radial direction of the rotor in the expanded state, which corresponds to at least 30%, in particular at least 50%, of the maximum height of the impeller elements. Furthermore, the rotor may be such that the reinforcing elements are surrounded over at least 90% of the surface, in particular 99%, more particularly the entire surface, by a plastic matrix which constitutes the majority of the rotor (42).

Claims

1. A rotor made of plastic reinforced with reinforcing elements for a compressible fluid pump radially deployable and compressible between a first state, a compressed state, and a second state, a deployed state, the reinforcing elements being in the form of fibers (10, 11, 13, 18, 19) or membrane strips whose length is at least three times their width, the reinforcing elements being distributed throughout and within one or more impeller elements of the rotor, the one or more impeller elements being reinforced by the reinforcing elements in the deployed state, the reinforcing elements being surrounded on all sides by injection molding material, The deployed state is a state in which no fluid resistance pressure is acting on the rotor, and in order to avoid the rotor overstretching from the deployed state when fluid resistance pressure is acting on the rotor, the reinforcing elements are stretched from their curved state in the compressed state in the deployed state, and are present in a form in which the distance between the two ends of the reinforcing elements is at least 90% of the length of the reinforcing elements along the reinforcing elements themselves.

2. 2. A rotor according to claim 1, characterized in that the reinforcing elements in the second state, the deployed state, are in an extended form from a curved state to an extent that the distance between both ends of the reinforcing elements is increased by less than 5% when the rotor transitions to a third state, which constitutes an operating state in which a fluid resistance pressure acts.

3. 3. A rotor as claimed in claim 2, characterized in that in the second state, the deployed state, and / or in the third state, the operating state, of the rotor, at least some of the groups of the reinforcing elements extend from a curved state to a straight state in at least one curved region of the impeller element.

4. 4. A rotor according to claim 3, characterized in that in the curved region of the impeller element, the reinforcing elements belonging to at least two groups each extend from a curved state to a straight state, and the extension directions of the reinforcing elements belonging to the groups are parallel within the same group but different between different groups.

5. A rotor according to any one of the preceding claims, characterized in that at least 30% of the reinforcing elements have a length greater than the average thickness of the impeller element.

6. A rotor according to any one of claims 1 to 5, characterized in that the rotor has a rotor hub, and the reinforcing element extends in a partially curved direction at the interface between the rotor hub and the impeller element.

7. A rotor according to any one of claims 1 to 6, characterized in that a first group of more than 30% of the reinforcing elements (10, 11, 13, 18, 19) in the deployed state of the rotor (42) extend from a substantially curved state from a portion (10a, 11a, 13a) arranged closest to the rotation axis of the rotor to a second portion (10b, 11b, 13b) arranged further from the rotation axis.

8. 8. A rotor according to claim 7, characterized in that in the deployed state, each of the reinforcing elements (10, 11, 13, 18, 19) of the first group has an extension direction that deviates from a position perpendicular to the rotor axis by up to 45° towards the rotor axis.

9. A rotor according to any one of claims 7 or 8, characterized in that each of the reinforcing elements (10, 11, 13, 18, 19) of the first group extends along a longitudinal axis (44) of an impeller element.

10. A rotor according to any one of claims 7 to 9, characterized in that, when the rotor is in a deployed state, the length of the first group of reinforcing elements (10, 11, 13, 18, 19) is at least 10% of the radius of the rotor.

11. A rotor according to any one of claims 7 to 10, characterized in that the reinforcing elements (10, 11, 13, 18, 19) of the first group are fibres, the fibres having a diameter of less than 40 μm.

12. A rotor as claimed in any one of claims 7 to 11, characterized in that in the deployed state of the rotor, a group of the reinforcing elements extend transversely to the reinforcing elements of the first group, and the smaller of the angles between the direction of extension of the reinforcing elements of the one group and the direction of extension of the reinforcing elements of the first group is on average at least 30°.

13. A rotor according to any one of the preceding claims, characterized in that the impeller element (15) is made of a foam material.

14. A rotor according to any one of the preceding claims, characterized in that the reinforcing elements are surrounded, over at least 90% of their surface, by plastic which constitutes the bulk of the rotor.

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