Reversible fan and method for operating same

Abstract

2.1. The invention relates to a reversible fan having a fan wheel (1) which rotates about a fan rotational axis (LD) and has a hub (2) and a plurality of fan blades (3) mounted on the hub so as to protrude radially and so as to be pivotal about a blade longitudinal axis (FL); a rotary drive for the fan wheel; and a pivoting device (5) for pivoting the fan blades. The rotary drive is designed to selectively drive the fan wheel in a first rotational direction for a first fan operating mode with a first conveying direction and in a second rotational direction opposite the first rotational direction for a second fan operating mode with a second conveying direction opposite the first conveying direction. The pivoting device is designed to pivot the fan blades between a first blade position for the first fan operating mode and a second blade position for the second fan operating mode, the same lateral edge (6) of each fan blade forming the leading edge thereof both in the first blade position and in the second blade position. The invention further relates to a method for operating a reversible fan. 2.2. According to the invention, the pivoting device is designed to pivot each pair of adjacent fan blades (3m, 3m+1) between the first blade position and the second blade position in opposite directions or in the same direction with a phase shift 2.3. The invention also relates to a use, for example for cooling fans of construction machines and agricultural machines.

Description

[0001] Reversing fans and operating procedures

[0002] The invention relates to a reversing fan according to the preamble of claim 1 and to a method for operating a reversing fan. In this context, a reversing fan is understood to be a fan, often also referred to as a ventilator, blower, etc., which can be operated selectively in one of two operating modes with the direction of flow of the medium it generates reversed, wherein the medium conveyed can be any fluid or gaseous medium, in particular air.

[0003] Reversible fans are used, for example, in the ventilation systems of heavy machinery such as construction equipment, tractors, combine harvesters, and other agricultural machinery. In these applications, they serve, for instance, to supply air from a radiator to an engine in one operating mode as a suction or blowing fan, and in a second operating mode as a blowing or suction fan to supply the radiator with a cleaning airflow, thereby removing accumulated dirt. Reversible fans are also used for various other ventilation tasks, such as in ventilation systems in tunnel construction for tunnel ventilation and in mining for mine ventilation, in building ventilation, for air, water, and heat pumps and air conditioning units, for off-road and on-road vehicles, in railway technology, especially for trains, etc.

[0004] The reversible fan under consideration, hereinafter also referred to simply as the fan, comprises, by its generic design, a fan wheel rotating about a fan axis, a rotary drive for the fan wheel, and a pivoting mechanism for pivoting the fan blades. The fan wheel includes a hub and a plurality of fan blades, which are mounted radially outward from the hub and pivotable about a longitudinal axis. The rotary drive is configured to selectively drive the fan wheel in a first direction of rotation for a first fan operating mode, in which the fan conveys the medium in a first conveying direction, and in a second fan operating mode, in which the fan conveys the medium in a second conveying direction opposite to the first conveying direction.The pivoting mechanism is designed to pivot the fan blades between a first blade position for the first fan operating mode and a second blade position for the second fan operating mode. In both fan operating modes, the same side edge of each fan blade forms its leading edge, i.e., its leading side edge in the respective direction of rotation of the fan.

[0005] It is generally known for reversing fans that the direction of flow can be reversed by pivoting the fan blades, usually by adjustment angles less than 180°, and / or by reversing the direction of fan rotation, as mentioned, for example, in the patent application DE 10 2019 134 887 A1, in which a specific mechanism for pivoting the fan blades using a planetary gear is disclosed.

[0006] A reversing fan of this type is disclosed in German patent application DE 102018 106454 A1. In the reversing fan described therein, the fan blades are pivoted synchronously, i.e., simultaneously with the same angle and direction of rotation, by approximately 180° from the first to the second blade position and back again. This synchronous 180° pivoting means, among other things, that all fan blades simultaneously assume specific intermediate positions, sometimes a transverse position and at other times an inverted position.

[0007] The inverted position, as used here, refers to the position in which the fan blade lies essentially in the plane of rotation of the fan, which is understood to be the plane perpendicular to the fan's axis of rotation. The transverse position, as used here, refers to the position of the respective fan blade pivoted by 90° relative to the inverted position, in which its blade lies essentially in a plane parallel to the fan's axis of rotation and thus perpendicular to the fan's plane of rotation. To prevent adjacent fan blades, i.e., those successive in the direction of rotation, from interfering with or blocking each other during the adjustment movement according to DE 10 2018 106 454 A1, the fan blades are designed and arranged such that, viewed in projection onto the fan's axis of rotation and thus onto the fan's plane of rotation, they do not overlap in any position, so that in the relevant intermediate inverted position, all fan blades, i.e.,The blades of all fan blades can lie essentially in the same plane, specifically the plane of rotation of the fan. As an alternative to the generic type of reversing fan considered here, another type of reversing fan is known in which the fan direction of rotation, i.e., the rotation direction of the fan blades, is maintained for the two operating modes with opposite conveyance directions; see, for example, patents DE 10 2013 008 902 B3, EP 3 743 626 B1, and EP 3 768 977 B1. For reversing the conveyance direction, in this type, the fan blades are pivoted synchronously across their inverted or transverse position by an angle of less than 180°, e.g., by an angle between approximately 120° and 150°. Pivoting across the transverse position is also possible in cases where the fan blades overlap in projection to the fan's axis of rotation; however, the leading and trailing edges of the fan blade are interchanged.its leading and trailing edges in the direction of fan rotation. Since the leading edge and the trailing edge are advantageously designed differently for aerodynamic optimization, this swapping of the leading and trailing edges changes the aerodynamic behavior of the fan blade.

[0008] The invention addresses the technical problem of providing a reversing fan of the type mentioned above, which, compared to the prior art mentioned above, offers greater freedom and flexibility with regard to the design and arrangement of the fan blades and can therefore be adapted in an improved manner to the respective application in terms of its conveying capacity and aerodynamic behavior, particularly with regard to high efficiency and low noise emissions. The invention also addresses the technical problem of providing an operating method that is particularly suitable for such a reversing fan.

[0009] The invention solves this problem by providing a reversing fan with the features of claim 1 and an operating method with the features of claim 13. Advantageous embodiments of the invention are specified in the dependent claims, the wording of which is hereby incorporated into the description by reference. This includes, in particular, all embodiments of the invention resulting from the combinations of features defined by the cross-references in the dependent claims. In the reversing fan according to the invention, the pivoting device is configured to pivot adjacent fan blades, i.e., those successive in the direction of fan rotation, in opposite directions or in the same direction with a phase shift between the first blade position and the second blade position.In this context, phase shift refers to a difference in the rotation angles by which one of two adjacent fan blades pivots earlier or later and / or at a different speed relative to the other. Opposite pivoting of adjacent fan blades is particularly suitable for fan designs with an even number of blades, while phase-shifted pivoting of adjacent fan blades in the same direction is generally suitable for both inverting fans with an even number of blades and inverting fans with an odd number of blades.

[0010] The invention thus enables collision-free pivoting of the fan blades between their first blade position, which is intended for operation of the fan in the first fan operating mode, and their second blade position, which is intended for operation of the fan in the second fan operating mode. This also applies to fan designs in which the fan blades, when viewed in projection onto the fan's rotational plane, overlap with their blades in corresponding rotational positions, such as in rotational positions in which the respective blade plane forms only a small angle of, for example, 45° or less with the fan's rotational plane. In normal fan operation, all fan blades form the same angle with the fan's rotational plane with their respective blade planes. Such fan designs prove to be advantageous for a wide variety of applications with regard to high efficiency and low noise generation.The invention also enables a blade change for such fan designs, i.e. a pivoting of the fan blades between the two blade positions for the two different fan operating modes, by, for example, 180°, which in conjunction with the reversal of the fan rotation direction corresponds to a point mirroring of the fan configuration and enables practically identical fan behavior in the two fan operating modes.

[0011] Thus, compared to the conventional synchronous pivoting of all fan blades, the invention offers more freedom and flexibility for the design and arrangement of the fan blades, and therefore more freedom for the optimal design and tuning of the reversing fan with regard to its intended application, particularly concerning its conveying capacity and aerodynamic behavior. Furthermore, the invention provides freedom and flexibility with regard to the switching movement of the fan blades between the two blade positions or fan operating modes, adapting to the specific application. Depending on the application, the switching movement of the fan blades can be achieved through counter-rotating blades without phase shift or with a predefinable rotation angle offset, or through phase-shifted, unidirectional rotating blades with a corresponding predefinable fixed phase shift contribution and / or different rotation speeds.Different rotational speeds of the swivel movement can be selected.

[0012] In a further development of the invention, the pivoting device is configured to pivot a first group of next-but-one fan blades synchronously between the first blade position and the second blade position, and to pivot a second group of intermediate next-but-one fan blades synchronously and in the opposite direction to the first group of next-but-one fan blades between the first blade position and the second blade position.

[0013] This represents a structurally simple and functionally advantageous implementation of opposing pivoting of adjacent fan blades. The fan blades of each group pivot synchronously with one another, for which structural designs known for such synchronous fan blade pivoting can be used. Since the fan blades of the two groups are arranged alternately in the fan's direction of rotation, the opposing pivoting of adjacent fan blades allows for unimpeded, collision-free pivoting of the fan blades even across the inversion position, i.e., the blade position in the fan's rotational plane, as is necessary, for example, for a pivot angle of 180°, even if the blades overlap in projection onto the fan's rotational plane during normal fan operation in the first or second fan operating mode.

[0014] In alternative configurations, the fan blades of the same group can also be pivoted non-synchronously, e.g., with a phase shift and / or at different pivoting speeds, for which the pivoting mechanism is then appropriately configured. In particular, the pivoting mechanism can, if required, be configured to pivot the fan blades of one group at the same or different pivoting speeds and in the opposite direction to the other group, whereby the opposite pivoting can again be performed with or without a phase shift.Alternatively, it is also possible to pivot each fan blade or only a part of the fan blades without a fixed reference to the pivoting of the other fan blades, whether in the opposite or same direction to neighboring fan blades, if this offers advantages for corresponding applications despite the usually greater effort required for individual control of the pivoting of the fan blade(s) in question.

[0015] In one embodiment of the invention, the pivoting device includes a gear coupling which, on the foot end of each fan blade, has a partially toothed pinion body with a toothed pinion circumferential section and an untoothed pinion circumferential section, and on the hub end, two gear bodies arranged axially offset parallel to the fan axis of rotation and held on a hub body so as to be rotatably movable relative to it, between which the pinion bodies of the fan blades are located and which each have alternating toothed and untoothed side sections in the circumferential direction. The toothed side sections of one gear body are opposite the untoothed side sections of the other gear body, and the toothed pinion circumferential sections of each pair of adjacent fan blades mesh with the toothed sections of each of the gear bodies.The term coupling is to be understood in a broad sense here and therefore basically includes any type of coupling of the components involved, in particular also in the form of a gearbox or gearbox coupling.

[0016] This represents a structurally simple and operationally reliable and robust implementation for the synchronous pivoting of the fan blades between their two blade positions for the two fan operating modes, both within the group and in opposite directions between the two groups. Due to the special design and arrangement of the two gear ring bodies, all fan blades can be pivoted in this way by the gear ring bodies performing a corresponding, limited rotational movement relative to the hub body. This adjustment movement of the gear ring bodies can, for example, be driven solely by inertia without an independent, additional drive, as is generally known from the aforementioned prior art. In this case, the moment of inertia of the rotating components of an output-side fan drive section ensures the necessary movement after the fan drive is switched off or decelerated.of the drive-side fan part, for the relevant relative movement of the gear ring body relative to the hub body, wherein this relative rotational movement is limited by respective stops in such a way that the fan blades pivot as desired from the first to the second blade position or from the second to the first blade position.

[0017] In a further embodiment of the invention, the toothed pinion circumferential sections and the untoothed pinion circumferential sections of the partially toothed pinion bodies each extend over approximately half the circumference of the partially toothed pinion bodies. This represents a structurally advantageous design for the pinion bodies of the fan blades that mesh with the gear ring bodies, particularly enabling the fan blades to pivot by at least approximately 180°.

[0018] In a further embodiment of the invention, the partially toothed pinion bodies are conical, and the gear ring bodies are bevel gear-shaped. This represents a structurally and functionally advantageous design for the meshing, i.e., engaging tooth coupling components in the form of the pinion bodies of the fan blades on the one hand and the gear ring bodies on the other.

[0019] In one embodiment of the invention, the pivoting device includes a rack and pinion coupling which, on the foot end of each fan blade, has a pinion body coaxial to the blade's axis of rotation and, on the hub end, a rack and pinion coupling body held axially movable parallel to the fan's axis of rotation on a hub body. This coupling body has rack sections projecting axially from a circumferential area, each of which meshes with one of the pinion bodies. Specifically, the pinion bodies of each pair of adjacent fan blades mesh with their respective associated rack sections in opposite directions of rotation.

[0020] This represents a further advantageous implementation of the pivoting device when adjacent fan blades are to be pivoted in opposite directions between their two blade positions. By corresponding axial movement of the rack and pinion coupling body relative to the hub body, all fan blades can be pivoted as desired, specifically adjacent fan blades in opposite directions. To effect the axial movement of the rack and pinion coupling body, the pivoting device can be equipped with any suitable, known drive. The opposite pivoting of any two adjacent fan blades can be easily achieved, for example, by having the relevant rack sections of the rack and pinion coupling body engage with the two associated fan blade pinion bodies on opposite sides, e.g.one rack section with a front side of the associated pinion body in the direction of fan rotation and the other rack section with a rear side of the pinion body of the adjacent fan blade in the direction of fan rotation.

[0021] In a further embodiment of the invention, the pivoting device features a pneumatic or hydraulic drive for the axial actuation of the rack and pinion coupling body. This represents an advantageous design of the pivoting device for axially movable rack and pinion coupling bodies. Such pneumatic or hydraulic drives can be implemented with relatively little design effort and in a space-saving manner, as is known for the fan blade pivoting of reversing fans. Alternatively, the pivoting device can also be equipped with a different axial actuator for the rack and pinion coupling body, such as a magnetic or electromagnetic drive.

[0022] In a further development of the invention, the pivoting device is configured to pivot a first group of next-but-one fan blades synchronously between the first blade position and the second blade position, and to pivot a second group of intermediate next-but-one fan blades synchronously and in the same direction relative to the first group of next-but-one fan blades between the first blade position and the second blade position.

[0023] This represents an advantageous and technically relatively simple implementation of the pivoting device for the case of phase-shifted, synchronous pivoting of any two adjacent fan blades. Within the group, the fan blades are again pivoted synchronously with each other in a simple manner, and the pivoting device further ensures that the fan blades of the two groups, arranged alternately in the direction of fan rotation, are pivoted in the desired phase-shifted, synchronous direction relative to each other. The phase shift, i.e., the rotational or pivoting angle offset, can again be appropriately adapted to the respective application, whereby, depending on requirements, it can be a rotational angle offset that remains constant or changes during pivoting.In particular, this ensures that, despite adjacent fan blades pivoting in the same direction at the same initial angle, the fan blades can pass through their transition position—the most critical position in this respect—without collisions, without necessarily requiring that the blades, when viewed from the fan's rotational plane, must not overlap in any rotational position. This is because the rotational angular offset ensures that adjacent fan blades pass through the transition position at different times during the transition movement, so that they do not interfere with each other in the transition position, even if, for example, their blades overlap when viewed from the fan's rotational plane in their normal operating position.

[0024] In one embodiment of the invention, the phase-shifted, co-directional pivoting of the second group of intermediate fan blades relative to the first group of fan blades comprises a co-directional pivoting with a constant phase shift contribution, i.e., a constant rotational angular offset contribution, and / or with different pivoting speeds, wherein in the latter case the phase shift, i.e., the rotational angular offset, changes due to the different pivoting speeds during the pivoting, typically continuously. The constant phase shift contribution and / or the different pivoting speeds ensure, in a structurally simple manner, that adjacent fan blades with their blades pass their transition position without collision at different times.The constant phase shift contribution can be implemented, for example, by starting the pivoting of one group of next-but-one fan blades at a correspondingly different time interval than the pivoting of the other group of next-but-one fan blades, i.e., earlier or later. If different pivoting speeds are selected, the pivoting of all fan blades from their previous to their new position can begin, with the slower-pivoting blades then continuing to pivot further to their new position after the faster-pivoting blades have already reached their new position.

[0025] In a further embodiment of the invention, the constant phase shift contribution includes a rotational angular offset between the co-rotating movements of the two groups of next-but-one fan blades in a range between 60° and 120°. In corresponding embodiments, it can be between 80° and 100°, e.g., at approximately 90°. By selecting the constant phase shift in this range, the fan blades can also be easily rotated co-rotating by, for example, 180° for fan designs that, in their normal operating position (such as the first or second blade position), have a noticeable overlap in projection onto the fan's rotational plane. Alternatively, the constant rotational angular offset can also be selected to be less than 60° or greater than 120° if this is sufficient and advantageous for the applications in question.

[0026] In many applications, a phase shift of approximately 90° is advantageous because it allows the overlap of adjacent fan blades, when projected onto the fan's rotational plane, to be kept relatively small in all possible fan blade positions. Specifically, a 90° phase shift ensures that the fan blades of one group are in their transverse position, where their surface area is smallest when projected onto the fan's rotational plane, when the fan blades of the other group are in their inverted position, i.e., essentially in the fan's rotational plane, where their surface area is largest.This thus enables collision-free pivoting of the fan blades between their two blade positions for the two different fan operating modes, even in cases where adjacent fan blades in their operating position, such as in their first or second blade position, have a relatively large overlap in projection onto the fan circulation plane, as is preferred in many cases for highly efficient and low-noise reversing fans.

[0027] In a further embodiment of the invention, the pivoting speed of one group of intermediate fan blades beyond the next is at least one-third and at most two-thirds, in particular about half, of the pivoting speed of the other group of intermediate fan blades beyond the next. Selecting the difference between the two pivoting speeds in this range is relatively easy to implement in the design and advantageous for many applications. This usually ensures, even without an additional, fixed phase shift contribution, that adjacent fan blades reach their transition position at sufficiently different times and do not interfere with each other.

[0028] In one embodiment of the invention, the pivoting device includes a geared ring coupling which, on the respective fan blade of the first group of next-but-one fan blades, has a radially inner toothed pinion body at the base, coaxial to the blade rotation axis, on the respective fan blade of the second group of next-but-one fan blades, has a radially outer toothed pinion body at the base, coaxial to the blade rotation axis, and, on the hub side, has two geared ring bodies arranged radially offset with respect to the fan rotation axis, which are self-disengagingly and are rotaryally coupled to each other, and of which one is rotaryally coupled to a drive-side fan drive part and the other is held in a limited rotatable position relative to an output-side hub body, wherein a radially inner of the two geared ring bodies meshes with the radially inner toothed pinion bodies and a radially outer geared ring body meshes with the radially outer toothed pinion bodies.This allows for a structurally simple and functionally effective way to achieve a unidirectional pivoting of the fan blades for blade reversal.

[0029] The operating method according to the invention is suitable for operating a reversing fan, which has a fan wheel rotating about a fan axis of rotation, a hub, and a plurality of fan blades that are radially projecting and pivotably mounted on the hub about a radial axis of rotation, as is the case, for example, with the reversing fan according to the invention. The fan is selectively operated in a first fan operating mode, in which the fan wheel rotates in a first direction of rotation with a first conveyance direction and the fan blades are in a first blade position, and in a second fan operating mode, in which the fan wheel rotates in a second direction of rotation opposite to the first direction of rotation with a second conveyance direction opposite to the first, and the fan blades are in a second blade position different from the first.To switch between the first and second fan operating modes, adjacent fan blades are pivoted in opposite directions or in the same direction with a phase shift between the first and second blade positions, and the direction of rotation of the fan wheel is reversed. With this operating mode, and in particular with the aforementioned method of fan blade pivoting, the same effects and advantages are achieved as described above for the correspondingly configured reversing fan according to the invention, to which reference may be made.

[0030] Advantageous embodiments of the invention are illustrated in the drawings. These and further embodiments of the invention are explained in more detail below. The drawings show:

[0031] Fig. 1 shows a top view of a reversing fan in a first fan operating mode with a swiveling device with a gear coupling for swiveling adjacent fan blades in opposite directions.

[0032] Fig. 2 shows a side view of the reversing fan from Fig. 1.

[0033] Fig. 3 a sectional view along a line Ill-Ill of Fig. 1 ,

[0034] Fig. 4 is a sectional view along line IV-IV of Fig. 1 ,

[0035] Fig. 5 of the reversing fan in the top view of Fig. 1 in the opposite direction

[0036] Swiveling of adjacent fan blades by 60°,

[0037] Fig. 6 shows the side view of Fig. 2 in the fan blade position of Fig. 5,

[0038] Fig. 7 shows the sectional view of Fig. 3 in the fan blade position of Fig. 5,

[0039] Fig. 8 shows the sectional view of Fig. 4 in the fan blade position of Fig. 5,

[0040] Fig. 9 is a sectional view along line IX-IX of Fig. 6,

[0041] Fig. 10 is a sectional view along a line XX of Fig. 6,

[0042] Fig. 11 a sectional view along line XI-XI of Fig. 6, Fig. 12 the reversing fan in the top view of Fig. 1 after opposite pivoting of each adjacent fan blade by 120°,

[0043] Fig. 13 shows the side view of Fig. 2 in the fan blade position of Fig. 12,

[0044] Fig. 14 shows the sectional view of Fig. 3 in the fan blade position of Fig. 12.

[0045] Fig. 15 shows the sectional view of Fig. 4 in the fan blade position of Fig. 12.

[0046] Fig. 16 shows the sectional view of Fig. 9 in the fan blade position of Fig. 12.

[0047] Fig. 17 shows the sectional view of Fig. 10 in the fan blade position of Fig. 12.

[0048] Fig. 18 shows the sectional view of Fig. 11 in the fan blade position of Fig. 12.

[0049] Fig. 19 shows the reversing fan in the top view of Fig. 1 in a second fan operating mode after opposite pivoting of each adjacent fan blade by 180° and reversing the fan rotation direction.

[0050] Fig. 20 is a sectional view along a line XX-XX of Fig. 19,

[0051] Fig. 21 shows the side view of Fig. 2 in the fan blade position of Fig. 19,

[0052] Fig. 22 shows the sectional view of Fig. 3 in the fan blade position of Fig. 19.

[0053] Fig. 23 shows the sectional view of Fig. 4 in the fan blade position of Fig. 19.

[0054] Fig. 24 shows the sectional view of Fig. 20 for a variant of the reversing fan with a

[0055] Swiveling device with pneumatically driven rack and pinion coupling for swiveling adjacent fan blades in opposite directions,

[0056] Fig. 25 is the sectional view of Fig. 3 for the fan variant of Fig. 24 in the first fan operating mode, Fig. 26 is the sectional view of Fig. 4 for the fan variant of Fig. 24 in the first fan operating mode,

[0057] Fig. 27 shows the sectional view of Fig. 25 after opposite pivoting of adjacent fan blades by 60°,

[0058] Fig. 28 shows the sectional view of Fig. 26 after opposite pivoting of adjacent fan blades by 60°,

[0059] Fig. 29 shows the sectional view of Fig. 25 after opposite pivoting of adjacent fan blades by 120°,

[0060] Fig. 30 shows the sectional view of Fig. 26 after opposite pivoting of adjacent fan blades by 120°,

[0061] Fig. 31 shows the sectional view of Fig. 25 after opposite pivoting of adjacent fan blades by 180°,

[0062] Fig. 32 shows the sectional view of Fig. 26 after opposite pivoting of adjacent fan blades by 180°,

[0063] Fig. 33 shows the sectional view of Fig. 24 for a variant of the reversing fan with a pivoting device with a hydraulically driven rack and pinion coupling for pivoting adjacent fan blades in opposite directions.

[0064] Fig. 34 shows a top view of a reversing fan with a swiveling device with a gear coupling for swiveling adjacent fan blades in the same direction with different swiveling speeds.

[0065] Fig. 35 is a sectional view along line XXXV-XXXV of Fig. 34,

[0066] Fig. 36 is a sectional view along line XXXVI-XXXVI of Fig. 34,

[0067] Fig. 37 is a side view of the reversing fan from Fig. 34, Fig. 38 is a sectional view along line XXXVI II-XXXVI II from Fig. 37 and

[0068] Fig. 39 is a sectional view along line XXXIX-XXXIX of Fig. 37.

[0069] The figures illustrate exemplary embodiments of the reversing fan according to the invention. As can be seen therefrom, the reversing fan according to the invention comprises a fan wheel 1 rotating about a fan axis of rotation LD, which has a hub 2 and a plurality of fan blades 3 that are radially projecting and pivotably mounted on the hub 2 about a radial blade axis of rotation FD. The reversing fan according to the invention further comprises a rotary drive 4 for the fan wheel 1. The rotary drive 4 is configured to drive the fan wheel 1 selectively for a first fan operating mode in a first direction of rotation R1 with a first conveyance direction M1, and for a second fan operating mode in a second direction of rotation R2 opposite to the first direction of rotation R1 with a second conveyance direction M2 opposite to the first conveyance direction M1.Figures 1 and 2 show the reversing fan in the first operating mode for the embodiment in question, while Figures 19 to 21 show it in the second operating mode. The rotary drive 4 is of a fundamentally arbitrary type known to those skilled in the art for this purpose, and therefore requires no further explanation here. It is thus shown only schematically in block diagram form in Figure 20.

[0070] Furthermore, the reversing fan according to the invention has a pivoting device 5 for pivoting the fan blades 3 between a first blade position F1 for the first fan operating mode, as shown in Figures 1 and 2, and a second blade position F2 for the second fan operating mode, as shown in Figures 19 to 21. The blade positions F1 and F2 are represented in Figures 1 and 2 and Figures 19 to 21, respectively, as representative of one fan blade 3 each. mThe fan blades 3, arranged successively in the circumferential direction of the fan wheel, are explicitly designated. Furthermore, in this example, without loss of generality, the fan blades 3, in both the first blade position F1 and the second blade position, form an angle of approximately 45° with their blade plane FE to the fan rotation axis LD or to the fan rotation plane UE perpendicular to it, as can be seen particularly in Figures 2 and 21, whereby they are pivoted by approximately 180° between these two blade positions F1 and F2. The blade plane FE here refers to the plane in which the blade of the respective fan blade 3 is mainly located; the blade plane FE for fan blade 3 is shown as an example in the corresponding figures. mThe angle of the fan blades 3 is specified. It is understood that the angle of the fan blades 3 in normal fan operation, as in the first and / or second fan operating mode, can be selected appropriately depending on the application and is not limited to the shown angle of the blade plane FE at a 45° angle to the fan's rotation plane UE. Thus, this blade angle can be set to any desired value between 0° and 90°, depending on the application and the shape of the fan blades 3.

[0071] In both the first fan operating mode according to Figs. 1 and 2 and the second fan operating mode according to Figs. 19 to 23, an identical side edge 6 of the respective fan blade 3 forms its leading edge, i.e., its side edge lying away from the respective direction of rotation R1, R2, as can again be seen from Figs. 1 and 2 and 19 to 23.

[0072] The pivoting device 5 is designed to pivot adjacent fan blades in opposite directions or in the same direction with a phase shift, i.e., in the same direction with a constant phase shift and / or with different pivoting speeds, between the first blade position F1 and the second blade position F2. Adjacent blades are understood to be successive fan blades 3 in the circumferential direction of the fan wheel. In the corresponding figures, an arbitrarily selected fan blade 3 is shown. m the entirety of fan blades 3 and its two adjacent fan blades 3m in front of and behind them in the circumferential direction.! , 3 m+1 marked. This means that the two are marked for fan blade 3. m adjacent fan blades in the direction of the fan's circumference 3 m .-i , 3 m+1 in relation to fan blade 3 mThe pivoting device 5 can pivot in the opposite direction or in phase shift in the same direction between the first wing position F1 and the second wing position F2.

[0073] In the embodiments shown in Figs. 1 to 33, the pivoting device 5 is specifically designed to swivel the respective adjacent fan blades 3. m , 3 m+1 to pivot in opposite directions between the two blade positions F1 and F2. In alternative embodiments according to the invention, the pivoting device 5 is configured to pivot the respective adjacent fan blades 3. m , 3 m+1 to pivot in the same direction with a constant phase shift and / or different pivoting speeds between the two blade positions F1 and F2. Figures 34 to 39 illustrate such a design, in which the adjacent fan blades 3 m , 3 m+1with different swivel speeds, for example, with swivel speeds that differ by a factor of two.

[0074] In advantageous embodiments, the pivoting device 5, as in the examples of Figures 1 to 33, is configured to pivot a first group 3g of next-but-one fan blades 3 synchronously between the first blade position F1 and the second blade position F2, and to pivot a second group 3u of intermediate next-but-one fan blades 3 synchronously and in the opposite direction to the first group 3g of next-but-one fan blades 3 between the first blade position F1 and the second blade position F2. If the fan blades 3 are numbered in the fan circumferential direction with natural numbers 1, 2, 3, ..., the first group 3g of next-but-one fan blades 3 can, for example, be referred to as even-numbered fan blades and the second group 3u of intermediate next-but-one fan blades 3 as odd-numbered fan blades.

[0075] Instead of the opposing pivoting of the fan blades 3 shown in the examples in Figures 1 to 33, the pivoting device 5 in alternative embodiments, as in the example in Figures 34 to 39, is configured to pivot a first group of next-but-one fan blades 3, e.g., the aforementioned first group 3g, synchronously between the first blade position F1 and the second blade position F2, and to pivot a second group of intermediate next-but-one fan blades 3, e.g., the aforementioned second group 3u, synchronously and in the same direction, but out of phase with the first group of next-but-one fan blades, between the two blade positions F1 and F2. The phase shift of the pivoting in the same direction of each adjacent fan blade 3, such as the fan blade 3 m and 3 m+1or 3m.!, enables, in an analogous manner to the described opposing pivoting of adjacent fan blades 3, a collision-free, unimpeded rotation of all fan blades 3 from their first blade position F1 to their second blade position F2 and vice versa, particularly also in the case where adjacent fan blades 3 overlap in projection parallel to the fan rotation axis LD onto the fan rotation plane UE in the first and / or second blade position F1, F2. For this purpose, the phase shift is adjusted as required to the shape and position of the fan blades 3 or to their overlap in projection onto the fan rotation plane UE. In corresponding cases, this involves a constant rotational angular offset corresponding to the phase shift between the pivoting of the two groups of next-but-one fan blades 3 in a range between 60° and 120°, and in special cases between 90° and 100°.In further implementations, it is provided that the two groups of next-but-one fan blades 3 are pivoted in the same direction at two different pivoting speeds, either in combination with the aforementioned fixed phase shift or, as in the example of Figures 34 to 39, without a fixed phase shift. In still other implementations, each fan blade 3 or a part of the fan blades 3 can be pivoted in the same or opposite direction to a neighboring fan blade 3, regardless of the pivoting direction and / or the pivoting speed and / or the pivoting angle of other fan blades 3.

[0076] In corresponding embodiments, the pivoting device 5, as in the embodiment shown in Figures 1 to 23, includes a geared coupling which has a partially toothed pinion body 5a on the foot side of each fan blade 3, coaxial to the blade rotation axis FD, and two geared bodies 5b, 5c arranged axially offset from the fan rotation axis FD on the hub side, and held to a hub body 2a of the hub 2 so as to be rotatably movable relative to it. The partially toothed pinion bodies 5a each have a toothed pinion circumferential section 7a and an untoothed pinion circumferential section 7b and are located axially between the two geared bodies 5b, 5c. Each of the two gear bodies 5b, 5c has alternating toothed sections 8a and untoothed sections 8b in the circumferential direction, wherein the toothed sections 8a of one gear body 5b or 5c correspond to the untoothed sections 8b of the other gear body 5c or 5c.5b opposite each other and the toothed pinion circumferential sections 7a of the pinion body 5a of each of two adjacent fan blades 3. m , 3 m+1 The toothed sections 8a mesh with each of the gear ring bodies 5b, 5c. This embodiment of the pivoting device 5 is particularly evident from Figs. 3, 4, 7, 8, 10, 11, 14, 15, 17, 18, 20, 22 and 23.

[0077] In corresponding embodiments, as in the example shown in Figures 1 to 23, the toothed pinion circumferential sections 7a and the untoothed pinion circumferential sections 7b of the partially toothed pinion bodies 5a of the fan blades 3 each extend over approximately half the circumference of the pinion body 5a, as can be seen, among other places, in Figures 3, 4, 7, and 8. In corresponding embodiments, the partially toothed pinion bodies 5a, as in the example in Figures 1 to 23, are conical, and the gear ring bodies 5b, 5c are correspondingly bevel-shaped, as can be seen in Figures 10, 11, 17, 18, and 20. In alternative embodiments, the partially toothed pinion bodies 5a and the gear ring bodies 5b, 5c are of a different shape, e.g., disc-shaped or cylindrical.

[0078] In other embodiments, the pivoting device, as in the examples of Figures 24 to 33, includes a rack and pinion coupling which, on the foot end of each fan blade 3, has a pinion body 5d coaxial to the blade rotation axis FD and, on the hub end, a rack and pinion coupling body 9 held axially movable parallel to the fan rotation axis LD on a hub body 2a of the hub 2. The rack and pinion coupling body 9 includes axially projecting rack sections 9b from a circumferential region 9a, each of which meshes with one of the pinion bodies 5d, with the pinion bodies 5d of each pair of adjacent fan blades 3 m , 3 m+1in opposite directions of rotation with the respective associated rack section 9b. In other words, the rack coupling body 9 has a rack section 9b for each pinion body 5d, wherein the rack sections 9b are arranged successively in the circumferential direction at a distance from one another, corresponding to the fan blades 3 and their pinion bodies 5d, and each project axially from the circumferential region 9a of the rack coupling body 9.

[0079] In corresponding embodiments, the pivoting device 5 is configured to effect the pivoting of the fan blades 3 between their two blade positions F1 and F2 for the first and second fan operating modes, respectively, solely by utilizing an inertial effect, as is known per se for fan blade pivoting. For this purpose, a driven-side fan drive component is mounted in the hub 2 with limited rotational movement relative to a driven-side fan drive component. In normal fan operation, the designated rotary drive 4 drives the fan wheel 1 to rotate about the fan axis of rotation LD, being either part of or acting upon the driven-side fan drive component, which in turn drives the driven-side fan drive component in the hub 2. For blade pivoting, the rotary drive 4, and thus the driven-side fan drive component, is braked sufficiently quickly.The rotation is stopped, and due to the inertia of the rotating fan wheel components, the output-side fan drive part continues to rotate within the specified limited rotational range. The relative rotational movement between the output-side and drive-side fan drive parts in the hub 2 causes the desired pivoting of the fan blades 3. The embodiments shown in Figures 1 to 23 and 34 to 39 are suitable for this inertia-driven blade pivoting.

[0080] In the example shown in Figures 1 to 23, this is achieved by holding the output-side fan drive part, which accommodates the fan blades 3 and their partially toothed pinion bodies 5a, in the hub 2 with limited rotational movement relative to the two gear ring bodies 5b, 5c belonging to the drive-side fan drive part in the hub 2. To limit this rotational movement, cams 12 formed on the drive-side fan drive part engage in slots 13 formed on the output-side fan drive part. These slots extend circumferentially with a predefinable length, allowing the cams 12 to move along the slots 13. The length of the slots 13 determines the degree of limited relative rotational movement. The slots 13 and the cams 12 engaging in them are particularly visible in Figures 9 and 16.

[0081] In corresponding implementations, the pivoting device 5 has a pneumatic drive 10 for the axial actuation of the rack and pinion coupling body 9, as for example in the embodiment shown in Fig. 24. In this example, a pressure chamber 14 is formed in the hub 2, to which a compressible pressure medium, such as air, can be supplied via a supply line 15. By changing the pressure in the pressure chamber 14, the rack and pinion coupling body 9 is moved axially in the hub 2 relative to the stationary part of the hub 2, whereby the pivoting device 5 causes the vane to pivot.

[0082] In other embodiments, the pivoting device 5 has a hydraulic drive 11 for axially actuating the rack and pinion coupling body 9. Fig. 33 shows such an embodiment. In this case, a hydraulic chamber or piston chamber 16 is formed in the hub 2, to which a hydraulic fluid can be supplied via a fluid channel 17. By appropriately pressurizing the piston chamber 16 with the hydraulic fluid, the rack and pinion coupling body 9 is moved axially relative to the remaining part of the hub 2, which remains stationary. In corresponding embodiments, the pivoting device 5 includes, as in the embodiment shown in Fig.Figures 34 to 39 describe a gear coupling comprising, on the one hand, a radially inner toothed pinion body 5e on the foot side of each fan blade 3 of the first group of next-but-one fan blades 3, coaxial with the blade rotation axis FD, and, on the other hand, a radially outer toothed pinion body 5f on the foot side of each fan blade 3 of the second group of next-but-one fan blades 3, and two gear bodies 5g, 5h arranged radially offset with respect to the fan rotation axis FD, i.e., a radially inner gear body 5h and a radially outer gear body 5g. In the example shown, each of the two gear bodies 5g, 5h is provided with an annular gear ring on an axial end face.The radially inner pinion bodies 5e are located closer to the fan rotation axis FD than the radially outer pinion bodies 5f, and analogously, the tooth ring of the radially inner gear ring body 5h is located closer to the fan rotation axis FD than the tooth ring of the radially outer gear ring body 5g. The tooth ring of the radially inner gear ring body 5h meshes with the radially inner toothed pinion bodies 5e, and the tooth ring of the radially outer gear ring body 5g meshes with the radially outer toothed pinion bodies 5f.

[0083] Of the two gear ring bodies 5g, 5h, a first one, in the example shown the radially inner gear ring body 5h, is rotationally coupled to a drive-side fan drive part 4a in the hub 2, preferably by a rotationally fixed coupling, which in the example shown is realized by a polygonal connection 18, such as a hexagonal connection. The hub body 2a is held with limited rotational movement relative to the drive-side fan drive part 4a. For this purpose, in appropriate embodiments, one or, as in the example shown, several rotation-limiting stops 19 are formed on the drive-side fan drive part 4a, projecting radially outwards, against which corresponding, radially inwards projecting stops 20 on the hub body 2a come into contact.

[0084] The other gear ring body, in the example shown the radially outer gear ring body 5g, is mounted with limited rotational movement relative to the hub body 2a, in which the fan blades 3 are held. For this purpose, in corresponding embodiments, as shown, one or more rotation-limiting stops 24 are axially projecting from the radially outer gear ring body 5g, which engage in corresponding axial grooves of the hub body 2a and interact with its flanks as rotation-limiting counter-stops 25.

[0085] The two gear ring bodies 5g, 5h are automatically disengaged and rotatably coupled to each other. For this purpose, in appropriate versions, one or, as in the example shown, several spring-loaded detent cams 21 are inserted into corresponding bores.

[0086] 22 of one gear body, e.g., the radially inner gear body 5h, are inserted, which engage in corresponding detent recesses 23 of the other gear body, e.g., the radially outer gear body 5g. The automatic disengagement of the detent cams 21 from the detent recesses 23 is effected by utilizing the moment of inertia of the still rotating output-side fan drive part, in particular the hub body 2a and the fan blades 3 held thereon, which, as explained above, can also effect the blade pivoting.

[0087] The gear bodies 5g, 5h and the pinion bodies 5e, 5f are matched with their teeth such that, for blade reversal, the two groups of next-but-one fan blades 3 rotate at two different pivoting speeds. In the example shown, the pivoting speed of the group of next-but-one fan blades 3 coupled to the radially outer gear body 5g, which has the radially outer pinion body 5f, is greater than the pivoting speed of the group of next-but-one fan blades 3 coupled to the radially inner gear body 5h, which has the radially outer pinion body 5e. For this purpose, the tooth pitch for the radially outer gear body 5g and the corresponding radially outer pinion bodies 5e can be chosen to be closer than for the radially inner gear body 5h and the corresponding radially inner pinion bodies 5f.The smaller swivel speed can be, for example, one third to two thirds of the larger swivel speed; in particular, it can be chosen to be about half as large for appropriate designs.

[0088] Analogous to the opposite wing pivoting in the embodiment shown in Fig. 1 to

[0089] In the embodiment shown in Figures 34 to 39, the rotary drive 4 and thus the drive-side fan drive part 4a are sufficiently decelerated or stopped in the same direction as the blades pivot. This also stops the rotationally fixed gear body 5h (here the radially inner gear body) and the other gear body 5h (here the radially outer gear body) that is engaged with it. Due to the inertia of the rotating fan components, the output-side fan drive part, and thus in particular the hub body 2a together with the fan blades 3, continues to rotate within the specified limited rotational range about the fan axis LD, i.e., until the hub body 2a with its stops 20 comes to rest against the stops 19 of the drive-side fan drive part 4a.As a result, the pinion bodies 5e, 5f of the continuously rotating fan blades 3 roll on the corresponding toothed rings of the stationary toothed ring bodies 5g, 5h, causing the pivoting of the fan blades 3 about their blade rotation axis FD to begin, as explained, with different pivoting speeds, i.e. in the chosen example the fan blades 3 with the radially outer pinion body 5f faster than the fan blades 3 with the radially inner pinion body 5e.

[0090] As soon as the rotating hub body 2a, with its counter-stops 25, comes into contact with the stops 24 of the stopped radially outer gear body 5g, the detent coupling of the radially outer gear body 5g with the radially inner gear body 5h is disengaged by the inertial effect, as the detent cams 21 move out of the detent recesses 23. In this position of the hub body 2a, the rapidly pivoting fan blades 3, together with the radially outer pinion body 5f, have reached their desired new blade position. The radially outer gear body 5g, no longer coupled to the radially inner gear body 5h due to the inertial disengagement, subsequently rotates with the hub body 2a and the fan blades 3 around the fan axis of rotation LD, so that the fan blades 3, together with the radially outer pinion body 5f, no longer pivot further and maintain their blade position.In contrast, the fan blades 3, which pivot more slowly, are pivoted further by rolling their radially inner pinion body 5e further on the stationary, radially inner gear ring body 5h.

[0091] As soon as the rotating hub body 2a, with its radially inwardly projecting stops 20, comes into contact with the stops 19 of the drive-side fan drive component 4a, the rotational movement of the hub body 4a also stops, and thus the inertial rotation of all driven-side components ceases. In this position, the fan blades 3, which pivot more slowly, have also reached their desired new blade position with the radially inner pinion body 5e. This completes the pivoting of the fan blades 3 in the same direction from their first blade position F1 for the first fan operating mode to their second blade position F2 for the second fan operating mode, or vice versa, from their second blade position F1 for the second fan operating mode to their first blade position F2 for the first fan operating mode.

[0092] Figures 1 to 23 illustrate, by way of example, the pivoting of the fan blades 3 from their first blade position F1 to their second blade position F2 by means of the pivoting device 5 equipped with the geared coupling in successive stages, based on suitable different views of the fan wheel 1 and the other components of the reversing fan involved in the pivoting, in particular the pivoting device 5 with its geared coupling, which comprises the blade-side partially toothed pinion bodies 5a and the hub-side geared body 5b, 5c.

[0093] Figures 1 to 4 illustrate the initial position in which the reversing fan is operated in the first fan operating mode, in which the fan blades 3 are in their first blade position F1, in this case with their blade plane FE at an angle of approximately 45° to the fan rotation plane UE. In other embodiments, this angle can, as mentioned above, have a different value in the range between 0° and 90°, preferably between 0° and 50°. Figures 1 and 2 show the fan wheel in a top and side view, respectively. Figures 3 and 4 are sectional views showing the relevant components of the pivoting device 5, i.e., the blade-side partially toothed pinion bodies 5a and the hub-side gear ring bodies 5b, 5c, in the area of ​​a fan blade.

[0094] 3 of the first group 3g, e.g. of the fan blade 3 m , or in the area of ​​a fan blade 3 of the second group 3u, e.g. fan blade 3m.! or 3 m+1 , show.

[0095] Figures 5 to 8 show the reversing fan in corresponding views as shown in Figures 1 to 8.

[0096] 4 after a synchronous pivoting of the first fan blade group 3g by an angle β1 of approximately 45° and a counter-clockwise synchronous pivoting of the second fan blade group 3u, i.e., by the angle -β1. As can be seen from Figures 5 and 6, the fan blades 3 of the first group 3g essentially assume their inverted position, i.e., their blade plane FE is essentially parallel to the fan rotation plane UE, while the fan blades 3 of the second group 3u essentially assume their transverse position, i.e., their blade plane FE is essentially perpendicular to the fan rotation plane UE. As can be further seen from Figures 5 and 6, the fan blades 3 of the first group 3g, like the fan blade 3 m, unhindered by the respective adjacent fan blades 3 of the second group 3u, like the fan blade 3m.! and 3 m+1 pivot across their transverse position, since the fan blades 3 of the second group 3u are in or near their transverse position, in which they have the smallest extent in projection onto the fan orbital plane UE.

[0097] Fig. 7, in comparison to Fig. 3, shows that the two gear bodies 5b, 5c have rotated slightly, and that gear body 5b meshes with the partially toothed pinion body 5a of the fan blade 3 of the first group 3g, rotating this pinion body 5a and thus the respective fan blade 3 by approximately 45° counterclockwise. Fig. 8, in comparison with Fig. 4, shows that, due to the rotation of the two gear bodies 5b, 5c, gear body 5c meshes with the partially toothed pinion body 5a of the fan wheel 3 of the second group 3u, thereby rotating this pinion body 5a and thus the fan blade 3 of the second group 3u by approximately 45° clockwise.

[0098] Fig. 9 shows that the relative rotation of the gear bodies 5b, 5c relative to the hub body 2a, which remains stationary, causes the cams 12 to move from their end position in the slots 13 by the corresponding angle of approximately 45°. Figs. 10 and 11 show how the partially toothed pinion bodies 5a of the fan blades 3 mesh with the gear body 5c and the gear body 5b, respectively, or remain disengaged. The partially toothed pinion bodies 5a of the first fan blade group 3g mesh only with the gear body 5b, while the partially toothed pinion bodies 5a of the second fan blade group 3u mesh only with the gear body 5c. The untoothed sections 7b, 8b of the partially toothed pinion bodies 5a and the gear body 5b, respectively, ensure this functionality without any blockages occurring.

[0099] Figures 12 to 18 show the reversing fan in views corresponding to Figures 5 to 11 after a further rotation of the fan blades 3 by approximately 90°, i.e., after a total rotation angle β1 of approximately 135°. Again, as during the entire pivoting movement, the fan blades 3 of the first group 3g are pivoted synchronously with each other, i.e., with the same angular magnitude and in the same direction, as are the fan blades 3 of the second group 3u, but in the opposite direction to the fan blades 3 of the first group 3g.

[0100] Figures 12 and 13 show that the fan blades 3 of the first group 3g are essentially in their transverse position in this position, i.e., their blade plane FE is essentially perpendicular to the fan rotation plane UE, while the fan blades 3 of the second group 3u are in their inverted position, i.e., their blade plane FE is essentially parallel to the fan rotation plane UE. Figures 14, 15, 17, and 18 show that the gear ring bodies 5b, 5c, through their further rotation, have rotated the partially toothed pinion bodies 5a and thus the fan blades 3 by 90° compared to the position shown in Figures 5 to 8. As can be seen in Figure 16, the cams 12 have correspondingly rotated by 90° in the slots 13.

[0101] As can be seen from Figures 12 and 13, in this position the fan blades 3 of the second group 3u can now be pivoted freely beyond their inverted position by the adjacent fan blades 3 of the first group 3g, since the fan blades 3 of the first group 3g are now in or near their transverse position, in which their extent in projection onto the fan rotation plane UE is minimal. This measure of the opposing pivoting of the respective adjacent fan blades 3 m , 3 m+1Consequently, unimpeded pivoting of the fan blades 3 between their blade positions F1 and F2 is achieved for the two fan operating modes, without requiring that the fan blades 3 do not overlap in normal operation of the reversing fan, particularly in the first and / or second fan operating mode, when projected onto the fan circulation plane UE. Instead, the fan blades 3 can be designed relatively freely solely according to aerodynamic and / or noise-related considerations and, in particular, can have a shape by which adjacent fan blades 3, such as the exemplary fan blades 3, do not overlap. m and 3 m+1 or 3m! , in their operating position, i.e. for example in their first blade position F1 and / or in their second blade position F2, noticeably overlap in projection onto the fan circulation plane UE, as is the case in the examples shown, see Fig. 1 and 19.

[0102] Figures 19 to 23 illustrate the reversing fan after the fan blades 3 have pivoted into their second blade position F2, in which the reversing fan is ready for operation in the second fan operating mode. Compared to the position according to Figures 12 to 15, Figures 19 and 21 to 23 show that and how the fan blades 3 have rotated again by approximately 45°, with the blades 3 in the same group rotating synchronously, and the first group of blades 3g rotating in the opposite direction to the second group of blades 3u. As a result, all fan blades 3 now again assume the same angle of, for example, 45° to the fan's rotation plane UE with their blade plane FE. Thus, the total pivot angle β1 of the fan blades 3 from their first blade position F1 to their second blade position F2 is approximately 180°, which corresponds almost exactly to a point reflection of the fan blade configuration of the impeller 1.

[0103] Since the rotational direction of the fan wheel 1 is reversed for operation of the reversing fan in the second fan operating mode, i.e., the fan wheel 1 rotates in the second rotational direction R2 opposite to the first rotational direction R1 in the first fan operating mode, the same side edge 6 of each fan blade 3 acts as the leading edge for both the second and the first fan operating modes. This has the significant advantage that all fan blades 3 can be optimally designed with considerable design freedom according to aerodynamic and / or noise-related considerations.

[0104] For this reason, the reversing fan can be operated with virtually the same flow characteristics and performance in both the first and second fan operating modes. For example, the first fan operating mode, with rotation of the fan wheel 1 in the direction of rotation R1, e.g., clockwise, can be a suction operation, while the second fan operating mode, in which the fan wheel 1 rotates in the opposite direction R2, e.g., counterclockwise, can be a blowing operation.

[0105] In the case of the pivoting device 5 equipped with the rack and pinion coupling, the pivoting of the fan blades 3 between their two blade positions F1 and F2 occurs in a largely identical manner to that described above for the pivoting device 5 with the ring gear coupling. Figures 25 to 32 illustrate, in views analogous to Figures 3, 4, 7, 8, 14, 15, 22, and 23, the synchronous pivoting of the fan blades 3 by approximately 180° within each group and in opposite directions between the two groups 3g and 3u. Figures 25 and 26 illustrate the pivoting device with the pinion bodies 5d and the rack and pinion coupling body 9, or its rack sections 9b, in the initial position, in which the fan blades 3 are in the first blade position F1. As can be seen from this, the rack sections 9b of each adjacent fan blade 3 mesh with the pinion bodies 5d on opposite sides of the pinion bodies 5d, i.e. in Fig.25 the rack section 9b on a left side of the pinion body 5d of a fan blade 3 of the first group 3g, e.g. of the fan blade 3. m , and in Fig. 26 the rack section 9b with a right-hand side of the pinion body 5d of a fan blade 3 of the second group 3u, e.g. of the fan blade 3 m+1 .

[0106] Figures 27 and 28 illustrate, in views analogous to Figures 25 and 26 respectively, the reversing fan after a rotation of the fan blades 3 by a pivot angle β1 of approximately 45° by corresponding axial movement of the rack coupling body 9 and thus of its rack sections 9b, downwards in Figures 25 to 28. Since the rack section 9b in Figure 27 meshes on the left side of the pinion body 5d, it rotates the associated fan blade counterclockwise, while the rack section 9b in Figure 28, which meshes with the right side of the respective pinion body 5d, rotates the associated fan blade 3m+1 twisted clockwise.

[0107] Figures 29 and 30 illustrate the situation after a further rotation of the fan blades 3 by approximately 90°, in which the rack sections 9b have moved axially accordingly. Figures 31 and 32 illustrate the fully pivoted final position of the fan blades 3, in which they have reached their second blade position F2. For this to occur, the rack sections 9b have moved axially further, rotating the fan blades 3 by another approximately 45°, i.e., the fan blades 3 have been pivoted by an angular amount equal to the pivot angle of approximately 180° from their first blade position F1 to their second blade position F2.

[0108] The swivel angle β1 between the two blade positions F1 and F2 for the first and second fan operating modes is approximately 180° in the examples shown, as explained. However, depending on the application, it can also have any other value in the range of 90° to 270°, particularly in cases where the fan blades 3, in the two fan operating modes, form unequal angles with the fan's rotational plane UE, i.e., angles of attack. In general, the relationship β1 = 180° + a1 - a2 results for the swivel angle β1, where a1 and a2 denote the respective angles of attack of the fan blades 3, i.e., the angle of the blade plane FE to the fan's rotational plane UE, in the first and second operating modes, respectively.

[0109] As can be seen from the illustrated and further embodiments explained above, the invention provides a reversing fan and an associated operating method that enables very efficient operation of the reversing fan in each of its two operating modes, which are reversed or inverted with respect to the conveying direction M1, M2 of the medium it conveys, i.e., both in suction mode and in blowing mode. The pivoting of the fan blades 3 such that adjacent fan blades 3 m , 3 m+ 1. Phase-shifted in the same direction, i.e., in the same direction with a fixed phase shift amount and / or different swivel speeds, or swiveled in opposite directions, enables an unimpeded, blockage-free swiveling process even for designs where adjacent fan blades 3 m , 3 m+1. In their normal operating position, the fan blades overlap in the first and / or second fan operating mode when projected onto the fan circulation plane UE. Preferably, the pivoting of the next-but-one fan blades occurs synchronously; alternatively, however, a more individualized pivoting of the next-but-one fan blades is also possible through a non-synchronous pivoting process.

[0110] The pivoting device 5 and the rotary drive 4 of the reversing fan according to the invention are configured so that, in both fan operating modes, the same side edge 6 of each fan blade 3 forms its leading edge, i.e., in both suction and blowing modes of the fan. For this purpose, the fan blades 3 are pivoted by a sufficiently large pivot angle β1 between the two fan operating modes, and the fan is operated with the fan wheel 1 rotating in the opposite direction. This specific opposite or phase-shifted pivoting of adjacent fan blades 3 m , 3 m+1 and the reversal of the rotation direction R1, R2 also have the advantage that the fan blades 3 can be designed largely freely according to aerodynamic and / or noise-related considerations, so that good performance characteristics of the reversing fan can be achieved for both suction and blowing operation, and in both cases the same side edge 6 of each fan blade 3 acts as the leading edge. Depending on requirements, the same or different angles of attack of the fan blades 3 can be selected for the first or the second fan operating mode.

[0111] The reversing fan and the operating method according to the invention can be used to advantage for a wide variety of ventilation tasks, such as for heavy machinery in agriculture and for construction machinery, for ventilation systems in tunnel construction for tunnel ventilation and in mining for mine ventilation, in building ventilation, for air, water and heat pumps and air conditioning units, for off-road and on-road vehicles, in railway technology, in particular for trains, etc.

Claims

Patent claims 1. Reversing fan with - a fan wheel (1) rotating about a fan axis of rotation (LD), which has a hub (2) and a plurality of fan blades (3) which are radially projecting and pivotably mounted on the hub (2) about a radial blade axis of rotation (FD), - a rotary drive (4) for the fan wheel (1) which is configured to drive the fan wheel (1) selectively for a first fan operating mode in a first direction of rotation (R1) with a first conveying direction (M1) and for a second fan operating mode in a second direction of rotation (R2) opposite to the first direction of rotation (R1) with a second conveying direction (M2) opposite to the first conveying direction (M1), and - a pivoting device (5) for pivoting the fan blades (3) between a first blade position (F1 ) for the first fan operating mode and a second blade position (F2) for the second fan operating mode, - wherein in both fan operating modes an identical side edge (6) of the respective fan blade (3) forms its leading edge, characterized in that - the swivel device (5) is designed to swivel adjacent fan blades (3 m , 3 m+1 ) to pivot in opposite directions or in phase shift in the same direction between the first wing position (F1 ) and the second wing position (F2).

2. Reversing fan according to claim 1, further characterized in that the pivoting device (5) is configured to pivot a first group (3g) of next-but-one fan blades (3) synchronously between the first blade position (F1 ) and the second blade position (F2) and to pivot a second group (3u) of intermediate next-but-one fan blades (3) synchronously and in the opposite direction to the first group (3g) of next-but-one fan blades (3) between the first blade position (F1 ) and the second blade position (F2).

3. Reversing fan according to claim 2, further characterized in that the swivel device (5) includes a gear coupling which is attached to the respective The fan blade (3) has a partially toothed pinion body (5a) at its base, coaxial to the blade rotation axis (FD), with a toothed pinion circumferential section (7a) and an untoothed pinion circumferential section (7b), and at its hub side two gear ring bodies (5b, 5c) arranged axially offset parallel to the fan rotation axis (FD) and held on a hub body (2a) so as to be rotatably movable relative to it, between which the pinion bodies (5a) of the fan blades (3) are located and which each have alternating toothed and untoothed sections (8a, 8b) in the circumferential direction, wherein the toothed sections (8a) of one gear ring body (5b) are opposite the untoothed sections (8b) of the other gear ring body (5c) and the toothed pinion circumferential sections (7a) of each pair of adjacent fan blades (3) m , 3m+1 ) comb each of the gear ring bodies (5b, 5c) with the toothed sections (8a).

4. Reversing fan according to claim 3, further characterized in that the toothed pinion circumferential sections (7a) and the untoothed pinion circumferential sections (7b) of the partially toothed pinion bodies (5a) each extend over approximately half the circumference of the pinion body (5a).

5. Reversing fan according to claim 3 or 4, further characterized in that the partially toothed pinion bodies (5a) are conical and the gear ring bodies (5b, 5c) are bevel gear shaped.

6. Reversing fan according to claim 2, further characterized in that the pivoting device (5) includes a rack and pinion coupling which has a pinion body (5d) on the foot side of each fan blade (3) coaxially to the blade rotation axis (FD) and a rack and pinion coupling body (9) held axially movable on a hub body (2a) parallel to the fan rotation axis (FD), which has rack sections (9b) projecting axially from a circumferential region (9a) which mesh with each of the pinion bodies (5d), wherein the pinion bodies (5d) of each of two adjacent fan blades (3) m , 3 m+1 ) mesh in opposite directions of rotation with the respective associated rack section (9b).

7. Reversing fan according to claim 6, further characterized in that the pivoting device (5) has a pneumatic drive (10) or a hydraulic drive (11) for axial actuation of the rack coupling body (9).

8. Reversing fan according to claim 1, further characterized in that the pivoting device (5) is configured to pivot a first group of next-but-one fan blades (3) synchronously between the first blade position (F1 ) and the second blade position (F2) and to pivot a second group of intermediate next-but-one fan blades (3) synchronously and in the same direction relative to the first group of next-but-one fan blades (3) in the same direction between the first blade position (F1 ) and the second blade position (F2).

9. Reversing fan according to claim 8, further characterized in that the phase-shifted, co-directional pivoting of the second group of intermediate next-but-one fan blades (3) relative to the first group of next-but-one fan blades (3) comprises a co-directional pivoting with a constant phase shift contribution and / or with different pivoting speeds.

10. Reversing fan according to claim 9, further characterized in that the constant phase shift contribution includes a rotation angle offset between the co-directional pivoting of the two groups of next-but-one fan blades (3) in a range between 60° and 120°, in particular between 80° and 100°.

11. Reversing fan according to claim 9 or 10, further characterized in that the pivoting speed of one group of intermediate next-but-one fan blades (3) is at least one third and at most two thirds, in particular about half, of the pivoting speed of the other group of intermediate next-but-one fan blades (3).

12. Reversing fan according to one of claims 8 to 11, further characterized in that the swivel device (5) includes a gear coupling which On the one hand, on the respective fan blade (3) of the first group of next-but-one fan blades (3), a radially inner toothed pinion body (5e) is located coaxially to the blade rotation axis (FD) at the base, and on the respective fan blade (3) of the second group of next-but-one fan blades (3), a radially outer toothed pinion body (5f) is located coaxially to the blade rotation axis (FD) at the base, and on the other hand, two gear ring bodies (5g, 5h) arranged radially offset with respect to the fan rotation axis (FD), which are self-disengagingly rotaryally coupled to each other, and of which a first (5h) is rotaryally coupled to a drive-side fan drive part (4a) and a second (5g) is held to be rotatably movable relative to an output-side hub body (2a), wherein a radially inner (5h) of the two gear ring bodies (5g, 5h) meshes with the radially inner toothed pinion bodies (5e) and a radially outer (5g) of the two Gear body (5g,5h) with the radially outer toothed pinion bodies (5f).

3. Method for operating a reversing fan, which has a fan wheel (1) rotating about a fan axis of rotation (LD) with a hub (2) and a plurality of fan blades (3) which are radially projecting and pivotably mounted on the hub (2) about a radial blade axis of rotation (FD), in particular a reversing fan according to any one of claims 1 to 12, optionally in a first fan operating mode in which the fan wheel (1) rotates in a first direction of rotation (R1) with a first conveyance direction (M1) and the fan blades (3) are in a first blade position (F1), and a second fan operating mode in which the fan wheel (1) rotates in a second direction of rotation (R2) opposite to the first direction of rotation (R1) with a second conveyance direction (M2) opposite to the first conveyance direction (M1) and the fan blades (3) are in a different position from the firstsecond wing position (F2), characterized in that, for switching between the first and second fan operating modes, adjacent fan wings (3, m , 3 m+1 ) opposite or phase-shifted in the same direction between the first wing position (F1 ) and the second wing position (F2) and the direction of rotation of the fan wheel (1 ) is reversed.

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