Reversible fans and operating procedures

Abstract

2.1. The invention relates to a reversible fan with a fan impeller (1) rotating about a fan rotation axis (LD), which has a hub (2) and a plurality of fan blades (3) mounted on the hub so as to project radially apart and pivot about a blade longitudinal axis (FL), a rotary drive for the fan impeller, and a pivoting device (5) for pivoting the fan blades. The rotary drive is configured to selectively drive the fan impeller for a first fan operating mode in a first rotational direction with a first conveying direction, and for a second fan operating mode in a second rotational direction opposite to the first rotational direction with a second conveying direction opposite to 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, wherein an identical side edge (6) of the respective fan blade forms its leading edge 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 adjacent fan blades (3m, 3m+1) in opposite directions or out of phase in the same direction between the first blade position and the second blade position2.3. Use, for example, for cooling fans of construction machinery and agricultural machinery.

Description

[0001] The invention relates to a reversible fan according to the preamble of claim 1 and to a method for operating a reversible fan. A reversible fan is understood here to be a fan, often also referred to as a ventilator, blower, etc., that can be operated selectively in one of two operating modes with the conveying direction of the medium flow generated by it reversed. The conveyed medium can, in principle, be any fluid or gaseous medium, in particular air.

[0002] Reversible fans are used, for example, for ventilation fans in heavy-duty machinery such as construction machinery, tractors, combine harvesters, and other agricultural machinery. In these applications, they serve, for example, to supply air from a radiator to an engine that needs cooling in a first operating mode as a suction or blower fan, and in a second operating mode as a blower or suction fan to subject the radiator to a cleaning air stream, thereby freeing it of accumulated dirt. Reversible fans are also used for various other ventilation tasks, such as 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.

[0003] The reversible fan considered here, hereinafter also referred to as a fan for short, has a fan impeller rotating about a fan rotation axis, a rotary drive for the fan impeller, and a pivoting device for pivoting the fan blades. The fan impeller includes a hub and a plurality of fan blades which are mounted on the hub in a radially projecting manner so as to be pivotable about a blade longitudinal axis. The rotary drive is configured to selectively drive the fan impeller in a first rotational direction for a first fan operating mode, in which the fan conveys the medium in a first conveying direction, and in a second rotational direction opposite to the first rotational direction for 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 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. In both fan operating modes, the same side edge of the respective fan blade forms its leading edge, i.e., its leading side edge in the respective direction of rotation of the fan.

[0004] It is generally known for reversible fans that the reversal of the air flow direction can be achieved by pivoting the fan blades, usually by adjustment angles of less than 180°, and / or by reversing the direction of fan rotation, as mentioned, for example, in the published patent application DE 10 2019 134 887 A1, in which a specific mechanism for pivoting the fan blades using a planetary gear is disclosed.

[0005] A reversible fan of this type is disclosed in published patent application DE 102018 106 454 A1. In this reversible fan, the fan blades are pivoted synchronously, i.e., simultaneously with the same angle of rotation and the same direction of rotation, by approximately 180° from the first to the second blade position and back again to switch operating modes. The synchronous pivoting by 180° means, among other things, that all fan blades simultaneously assume a transverse position and a reverse position in special intermediate positions. In this case, the reverse position refers to the position in which the blade lies essentially in the fan's rotational plane, which is understood to be the plane perpendicular to the fan's rotational axis.In this case, the transverse position refers to the position of the respective fan blade pivoted by 90° relative to the reverse position, in which its blade lies essentially in a plane parallel to the fan rotation axis and thus perpendicular to the fan rotation plane. To ensure that adjacent fan blades, i.e. those following one another in the direction of fan rotation, do not interfere with or block one another during this adjustment movement, the fan blades are designed and arranged in such a way that, viewed in projection relative to the fan rotation axis and thus in projection relative to the fan rotation plane, they do not overlap one another in any position, so that in the respective reverse position intermediate position, all blades can lie essentially in the same plane, specifically the fan rotation plane.

[0006] As an alternative to the generic type of reversible fan considered here, another type of reversible fan is known in which the fan rotation direction, i.e. the direction of rotation of the fan blades, is retained for the two operating modes with opposite air flow directions, see e.g. the patents DE 10 2013 008 902 B3, EP 3 743 626 B1 and EP 3 768 977 B1. To reverse the air flow direction, in this type the fan blades are pivoted synchronously across their reverse position or their transverse position by an angle of less than 180°, e.g. by an angle between approximately 120° and 150°. The pivoting across the transverse position is also possible in cases where the fan blades are designed to overlap in projection to the fan rotation axis, but the leading edge and trailing edge of the fan blade are swapped, i.e. its front and rear edges in the direction of fan rotation.Since the leading edge and the trailing edge are designed differently for the purpose of aerodynamic optimization, this swapping of leading edge and trailing edge changes the aerodynamic behavior of the fan blade.

[0007] The technical problem underlying the invention is to provide a reversible fan of the type mentioned above, which, compared to the aforementioned prior art, allows greater freedom and flexibility with regard to the design and arrangement of the fan blades and which can thus 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 generation. The invention is also based on the technical problem of providing an operating method that is particularly suitable for such a reversible fan.

[0008] The invention solves this problem by providing a reversible fan with the features of claim 1 and an operating method with the features of claim 10. Advantageous developments of the invention are specified in the subclaims, the wording of which is hereby incorporated by reference into the description. This includes, in particular, all embodiments of the invention resulting from the combinations of features defined by the references in the subclaims.

[0009] In the reversible fan according to the invention, the pivoting device is designed to pivot adjacent fan blades, i.e. fan blades which follow one another 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 case, phase shift means the angle of rotation offset by which one of two adjacent fan blades is pivoted earlier or later than the other. The opposite pivoting of adjacent fan blades is particularly suitable for fan designs with an even number of fan blades, while the phase-shifted pivoting of adjacent fan blades in the same direction is generally suitable for reversible fans with an even number of fan blades as well as for reversible fans with an odd number of fan blades.

[0010] The invention thus enables collision-free pivoting of the fan blades between their first blade position, which is provided for operation of the fan in the first fan operating mode, and their second blade position, which is provided for operation of the fan in the second fan operating mode, even for fan designs in which the fan blades, as seen in projection onto the fan rotation plane, overlap with their blades in corresponding rotational positions, such as in rotational positions in which the respective blade plane only encloses a small angle of e.g. 45° or less with the fan rotation plane, wherein in normal fan operation all fan blades with their respective blade plane enclose the same angle with the fan rotation plane. Such fan designs prove to be advantageous for very many applications with regard to high efficiency and low noise generation.The invention also enables such fan designs to pivot 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 thus more freedom for the optimal design and coordination of the reversible fan with regard to its intended application, in particular with regard to its airflow capacity and aerodynamic behavior. In addition, 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 respective application. Depending on the case, a counter-direction blade pivoting without phase shift or with a predeterminable rotation angle offset, or a phase-shifted, same-direction pivoting with a correspondingly predeterminable rotation angle offset can be selected for the switching movement of the fan blades.

[0012] In a further development of the invention, the pivoting device is designed to pivot a first group of fan blades next but one synchronously between the first blade position and the second blade position and to pivot a second group of intermediate fan blades next but one synchronously and in the opposite direction to the first group of fan blades next but one 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 the respective group are pivoted synchronously with one another, for which structural designs can be used which are known per se for such synchronous fan blade pivoting. Since the fan blades of the two groups are arranged alternately in the direction of fan rotation, the opposing pivoting of the adjacent fan blades enables unhindered, collision-free pivoting of the fan blades even beyond the turnaround position, i.e. the blade position in the fan rotation plane, as is necessary, for example, for a pivot angle of 180°, even if the blades overlap in projection onto the fan rotation plane during normal fan operation in the first or second fan operating mode.

[0014] In alternative designs, the fan blades belonging to the same group can also be pivoted non-synchronously, e.g., out of phase and / or at different pivot speeds, i.e., the rotational speed of the pivoting movement, for which the pivoting device is then suitably configured. In particular, the pivoting device can, if required, be configured to pivot the fan blades of one group at the same pivot speed or at different pivot speeds and in opposite directions to the other group, whereby the opposite pivoting can again occur with or without phase shift.Furthermore, it is alternatively 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, be it in the opposite direction or in the same direction to adjacent fan blades, if this offers advantages for corresponding applications despite the then normally greater effort for individually controlling the pivoting of the fan blade(s) in question.

[0015] In one embodiment of the invention, the pivoting device comprises a gear ring coupling which, on the respective fan blade, has a partially toothed pinion body with a toothed pinion circumferential section and an untoothed pinion circumferential section on the base side coaxial with the blade rotation axis, and two gear ring bodies on the hub side, arranged axially offset parallel to the fan rotation axis and held on a hub body with limited rotational movement relative to the hub, between which the pinion bodies of the fan blades are located and which each contain toothed and untoothed side sections alternating in the circumferential direction. The toothed side sections of one gear ring body lie opposite the untoothed side sections of the other gear ring body, and the toothed pinion circumferential sections of any two adjacent fan blades mesh with the toothed sections of one of the gear ring bodies.The term clutch is to be understood in a broad sense here and therefore basically includes any type of coupling of the components involved with one another, in particular in the form of a gearbox or a gearbox coupling.

[0016] This represents a structurally simple and operationally reliable and robust implementation for the synchronous pivoting of the fan blades within the group and in opposite directions between the two groups between their two blade positions for the two fan operating modes. 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 rotary movement relative to the hub body. This adjustment movement of the gear ring bodies can, for example, be carried out solely by the moment of inertia without an independent, additional drive, as is basically known from the above-mentioned prior art. In this case, the moment of inertia of the rotating components of the output-side fan section ensures that, after the fan drive is switched off or braked, i.e.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 partial circumferential pinions. This represents a structurally advantageous design for many applications 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-shaped. This represents a structurally and functionally advantageous design for the meshing, i.e., meshing via their teeth, 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 coupling, which has a pinion body on the base side of each fan blade, coaxial with the blade rotation axis, and a rack coupling body on the hub side, which is held axially movable on a hub body parallel to the fan rotation axis. The rack 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 two adjacent fan blades mesh with the respective associated rack section 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 coupling body relative to the hub body, all fan blades can be pivoted in the desired manner, especially adjacent fan blades in opposite directions. To effect the axial movement of the rack coupling body, the pivoting device can be equipped with any suitable, known drive. The opposite pivoting of two adjacent fan blades can be achieved in a simple manner, for example, by the relevant rack sections of the rack coupling body engaging with the two associated fan blade pinion bodies on opposite sides thereof, 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 has a pneumatic or hydraulic drive for axially actuating the rack coupling body. This represents an advantageous embodiment of the pivoting device for the case of an axially movable rack coupling body. Such pneumatic or hydraulic drives can be implemented with relatively little design effort and in a space-saving manner, as is known per se for the fan blade pivoting of reversible fans. Alternatively, the pivoting device can also be equipped with another axial actuator for the rack coupling body, such as a magnetic or electromagnetic drive.

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

[0023] This represents an advantageous design of the pivoting device for the case of phase-shifted, co-rotation of two adjacent fan blades. Within the group, the fan blades are 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 same direction as desired, out of phase with each other. The phase shift, i.e., the rotation or pivot angle offset, can be suitably adjusted to the respective application.

[0024] In one embodiment of the invention, a rotational angle offset corresponding to the phase shift between the co-directional pivoting of the two groups of next-but-one fan blades lies in a range between 60° and 120°. In corresponding designs, it can in particular be between 80° and 100°, e.g., approximately 90°. By selecting a phase shift within this range, the fan blades can be easily pivoted in the same direction by, for example, 180°, even for fan designs that, in their normal operating position, such as in the first or second blade position, have a noticeable overlap in projection onto the fan rotation plane. Alternatively, the rotational angle offset can also be selected to be less than 60° or greater than 120° if this is sufficient and favorable for the respective applications.

[0025] In many applications, a phase shift of approximately 90° is advantageous, as it allows the overlap of adjacent fan blades, as projected onto the fan rotation plane, to be kept relatively small in all possible fan blade positions. A phase shift of 90° ensures, in particular, that the fan blades of one group are in their transverse position, in which their surface area is smallest as projected onto the fan rotation plane, when the fan blades of the other group are in their reverse position, i.e., essentially in the fan rotation plane, in which their surface area is greatest as projected onto the fan rotation plane.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 reversible fans.

[0026] The operating method according to the invention is suitable for operating a reversible fan having a fan impeller rotating about a fan rotation axis, with a hub and a plurality of fan blades that are radially spaced and pivotably mounted on the hub about a radial blade rotation axis, as is the case, for example, with the reversible fan according to the invention. The fan is operated optionally in a first fan operating mode, in which the fan impeller rotates in a first direction of rotation with a first conveying direction and the fan blades are in a first blade position, and a second fan operating mode, in which the fan impeller rotates in a second direction of rotation opposite to the first direction of rotation with a second conveying direction opposite to the first conveying direction 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 out of phase with the same direction between the first blade position and the second blade position, and the direction of rotation of the fan wheel is reversed. With this mode of operation, and in particular the aforementioned type of fan blade pivoting, the same effects and advantages are achieved as mentioned above for the correspondingly configured reversible fan according to the invention, to which reference can be made.

[0027] Advantageous embodiments of the invention are illustrated in the drawings. These and other embodiments of the invention are explained in more detail below. In the drawings: Fig. 1 a plan view of a reversible fan in a first fan operating mode with a swivel device with gear coupling for the opposite swiveling of adjacent fan blades, Fig. 2 a side view of the reversible fan of Fig. 1, Fig. 3 a sectional view along a line III-III of Fig. 1, Fig. 4 a sectional view along a line IV-IV of Fig. 1, Fig. 5 the reversible fan in the top view of Fig. 1 after opposing swiveling of adjacent fan blades by 60°, Fig. 6 the side view of Fig. 2 in the fan blade position of Fig. 5, Fig. 7 the sectional view of Fig. 3 in the fan blade position of Fig. 5, Fig. 8 the sectional view of Fig. 4 in the fan blade position of Fig. 5, Fig. 9 a sectional view along a line IX-IX of Fig. 6, Fig. 10 a sectional view along a line XX of Fig. 6, Fig. 11 a sectional view along a line XI-XI of Fig. 6, Fig. 12 the reversible fan in the top view of Fig. 1 after opposing swiveling of adjacent fan blades by 120°, Fig. 13 the side view of Fig. 2 in the fan blade position of Fig. 12, Fig. 14 the sectional view of Fig. 3 in the fan blade position of Fig. 12, Fig. 15 the sectional view of Fig. 4 in the fan blade position of Fig. 12, Fig. 16 the sectional view of Fig. 9 in the fan blade position of Fig. 12, Fig. 17 the sectional view of Fig. 10 in the fan blade position of Fig. 12, Fig. 18 the sectional view of Fig. 11 in the fan blade position of Fig. 12, Fig. 19 the reversible fan in the top view of Fig. 1 in a second fan operating mode after opposing swiveling of adjacent fan blades by 180° and reversing the direction of fan rotation, Fig. 20 a sectional view along a line XX-XX of Fig. 19, Fig. 21 the side view of Fig. 2 in the fan blade position of Fig. 19, Fig. 22 the sectional view of Fig. 3 in the fan blade position of Fig. 19, Fig. 23 the sectional view of Fig. 4 in the fan blade position of Fig. 19, Fig. 24 the sectional view of Fig. 20 for a variant of the reversible fan with a swivel device with pneumatically driven rack and pinion coupling for the opposite swiveling of adjacent fan blades, Fig. 25 the sectional view of Fig. 3 for the fan variant of Fig. 24 in the first fan mode, Fig. 26 the sectional view of Fig. 4 for the fan variant of Fig. 24 in the first fan mode, Fig. 27 the sectional view of Fig. 25 after opposing swiveling of adjacent fan blades by 60°, Fig. 28 the sectional view of Fig. 26 after opposing swiveling of adjacent fan blades by 60°, Fig. 29 the sectional view of Fig. 25 after opposing swiveling of adjacent fan blades by 120°, Fig. 30 the sectional view of Fig. 26 after opposing swiveling of adjacent fan blades by 120°, Fig. 31 the sectional view of Fig. 25 after opposing swiveling of adjacent fan blades by 180°, Fig. 32 the sectional view of Fig. 26 after opposing swiveling of adjacent fan blades by 180° and Fig. 33 the sectional view of Fig. 24 for a variant of the reversible fan with a swivel device with hydraulically driven rack and pinion coupling for counter-swivelling of adjacent fan blades.

[0028] The figures illustrate exemplary embodiments of the reversible fan according to the invention. As can be seen therefrom, the reversible fan according to the invention includes a fan wheel 1 rotating about a fan rotation axis LD, which has a hub 2 and a plurality of fan blades 3, which project radially and are mounted on the hub 2 so as to be pivotable about a radial blade rotation axis FD. The reversible fan according to the invention further includes 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 rotation direction R1 with a first conveying direction M1, and for a second fan operating mode in a second rotation direction R2 opposite to the first rotation direction R1 with a second conveying direction M2 opposite to the first conveying direction M1. Fig. 1 and Fig. 2 show the reversible fan in the first fan operating mode for the respective embodiment, the Fig. Figures 19 to 21 show it in the second fan operating mode. The rotary drive 4 is of any type known to the person skilled in the art for this purpose, which therefore requires no further explanation here. It is therefore Fig. 20 is shown only schematically in block diagram form.

[0029] Furthermore, the reversible 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 the Fig. 1 and Fig. 2, and a second blade position F2 for the second fan operating mode, as shown in the Fig. 19 to 21. The wing positions F1, F2 are shown in the Fig. 1 and Fig. 2 or the Fig. 19 to 21 each represent a fan blade 3 mof the fan blades 3 arranged consecutively in the circumferential direction of the fan wheel. Furthermore, in this example, without limiting the generality, the fan blades 3 in the first blade position F1 as well as in the second blade position enclose with their blade plane FE an angle of approximately 45° to the fan rotation axis LD or to the fan rotation plane UE perpendicular thereto, as can be seen in particular from the Fig. 2 and Fig. 21, whereby they are pivoted by approximately 180° between these two blade positions F1, F2. The blade plane FE refers to the plane in which the blade of the respective fan blade 3 is primarily located. The blade plane FE for fan blade 3 is shown as an example in the corresponding figures. mIt is understood that the angular position of the fan blades 3 during normal fan operation, such as in the first and / or second fan operating mode, can be suitably selected depending on the application and is not limited to the shown angular position of the blade plane FE at a 45° angle to the fan rotation plane UE. Thus, this blade position angle can be set to any desired value between 0° and 90° depending on the application and the shape of the fan blades 3.

[0030] Both in the first fan operating mode according to the Fig. 1 and Fig. 2 and in the second fan operating mode according to the Fig. 19 to 21, an identical side edge 6 of the respective fan blade 3 forms its leading edge, ie its side edge which is at the front in the respective direction of rotation R1, R2, as can again be seen from the Fig. 1 and 2 or 19 to 21.

[0031] The pivoting device 5 is designed to pivot adjacent fan blades in opposite directions or in the same direction with a phase shift between the first blade position F1 and the second blade position F2. Adjacent fan blades 3 are understood to be consecutive fan blades 3 in the circumferential direction of the fan wheel. In the corresponding figures, a randomly selected fan blade 3 is shown for this purpose. m the entirety of fan blades 3 and its two adjacent fan blades 3 in the circumferential direction in front of and behind it m-1 , 3 m+1 This means that the two fan blades 3 m adjacent fan blades 3 in the fan circumferential direction m-1 , 3 m+1 in relation to fan blade 3 m by the pivoting device 5 in the opposite direction or out of phase in the same direction between the first wing position F1 and the second wing position F2.

[0032] In the examples shown, the swivel device 5 is specially designed to rotate the adjacent fan blades 3 m , 3 m+1 in opposite directions between the two blade positions F1, F2. In alternative embodiments according to the invention, the pivoting device 5 is designed to pivot the adjacent fan blades 3 m , 3 m+1 to pivot in the same direction between the two wing positions F1, F2, out of phase.

[0033] In advantageous embodiments, the pivoting device 5, as in the examples shown, 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 counted in the fan circumferential direction using natural numbers 1, 2, 3, ..., the first group 3g of next-but-one fan blades 3 can be referred to, for example, as even-numbered fan blades, and the second group 3u of intermediate next-but-one fan blades 3 can be referred to as odd-numbered fan blades.

[0034] Instead of the opposite pivoting of the fan blades 3 realized in the examples shown, the pivoting device 5 is configured in alternative embodiments to pivot a first group of fan blades 3 next but one, 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 fan blades 3 next but one, e.g., the aforementioned second group 3u, synchronously and with a phase shift relative to the first group of fan blades next but one, in the same direction between the two blade positions F1, F2. The phase shift of the same-direction pivoting of adjacent fan blades 3, such as the fan blade 3 m and 3 m+1 or 3 m-1, enables, in a manner analogous to the explained opposite pivoting of adjacent fan blades 3, a collision-free, unhindered rotation of all fan blades 3 from their first blade position F1 to their second blade position F2 and vice versa, in particular also in the event that 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 matched 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, a rotational angle offset corresponding to the phase shift between the same direction pivoting of the two groups of next-but-one fan blades 3 lies in a range between 60° and 120°, in special cases between 90° and 100°.In further implementations not shown, it is intended to pivot the two groups of fan blades 3 next to each other in the same direction at two different pivoting speeds, either in combination with the aforementioned phase shift or without phase shift. In still other implementations, each fan blade or a portion of the fan blades can be pivoted in the same direction or in the opposite direction to a neighboring fan blade, regardless of the pivoting direction and / or pivoting speed and / or pivoting angle of other fan blades.

[0035] In corresponding embodiments, the pivoting device 5 includes, as in the embodiment of the Fig. 1 to 23, a ring gear coupling comprising a partially toothed pinion body 5a on the base side of the respective fan blade 3, coaxial with the blade rotation axis FD, and two ring gear bodies 5b, 5c on the hub side, arranged axially offset parallel to the fan rotation axis FD and held on a hub body 2a of the hub 2 with limited rotational movement relative to the latter. The partially toothed pinion bodies 5a each comprise a toothed pinion circumferential section 7a and an untoothed pinion circumferential section 7b and are located axially between the two ring gear bodies 5b, 5c. Each of the two gear ring bodies 5b, 5c has toothed sections 8a and untoothed sections 8b alternating in the circumferential direction, wherein the toothed sections 8a of one gear ring body 5b or 5c are opposite the untoothed sections 8b of the other gear ring body 5c or 5b and the toothed pinion circumferential sections 7a of the pinion bodies 5a of each two adjacent fan blades 3 m , 3 m+1mesh with the toothed sections 8a of each of the gear ring bodies 5b, 5c. This design of the pivoting device 5 is particularly evident from the Fig. 3, Fig. 4, Fig. 7, Fig. 8, Fig. 10, Fig. 11, Fig. 14, Fig. 15, Fig. 17, Fig. 18, Fig. 20, Fig. 22 and Fig. 23 can be seen.

[0036] In corresponding implementations, as in the example shown, the Fig. 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 over approximately half the circumference of the pinion body 5,a as shown, inter alia, in the Fig. 3, Fig. 4, Fig. 7 and Fig. 8 can be seen.

[0037] In corresponding implementations, the partially toothed pinion bodies 5a, as in the example of the Fig. 1 to 23, conical, and the gear ring bodies 5b, 5c are formed in a bevel gear shape, as can be seen from the Fig. 10, Fig. 11, Fig. 17, Fig. 18 and Fig. 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.

[0038] In other embodiments, the pivoting device includes, as in the examples of Fig. 24 to 33, a rack and pinion coupling, which has a pinion body 5d on the respective fan blade 3 on the base side coaxial with the blade rotation axis FD and a rack and pinion coupling body 9 on the hub side, which is 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 rack sections 9b projecting axially from a circumferential area 9a, which mesh with one of the pinion bodies 5d each, wherein the pinion bodies 5d of each two adjacent fan blades 3 m , 3 m+1mesh in opposite directions of rotation with the respectively 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 circumferentially spaced from one another in correspondence with the fan blades 3 and their pinion bodies 5d and each protrudes axially from the circumferential region 9a of the rack coupling body 9.

[0039] In corresponding embodiments, the pivoting device 5 is designed to pivot the fan blades 3 between their two blade positions F1, F2 for the first and second fan operating modes solely by utilizing an inertia effect, as is known per se for fan blade pivoting. For this purpose, a part on the output side is held in the hub 2 with limited rotational mobility relative to a part on the drive side. During normal fan operation, the rotary drive 4 provided for this purpose drives the fan wheel 1 to rotate about the fan rotation axis LD, acting on the part on the drive side in the hub 2, which drives the output side part with it. For the blade pivoting, the rotary drive 4 and thus the part on the drive side in the hub 2 are braked or stopped sufficiently quickly.stopped, and due to the inertia of the rotating fan wheel components, the output-side part in the hub 2 continues to rotate within the specified limited rotational range. The relative rotational movement between the output-side and drive-side parts in the hub 2 causes the desired pivoting of the fan blades 3. The embodiment of the . Fig. 1 to 23 is suitable for this inertia-driven blade pivoting. This is made possible by the fact that the output-side part, which accommodates the fan blades 3 and their partially toothed pinion bodies 5a, is held in the hub 2 with limited rotational mobility relative to the two gear ring bodies 5b, 5c, which belong to the drive-side part in the hub 2. To limit this rotational mobility, in this embodiment, cams 12, which are formed on the drive-side part, engage in slots 13, which are formed on the output-side part and extend with a predeterminable length in the circumferential direction, so that the cams 12 can move along the slots 13 and the length of the slots 13 determines the degree of limited relative rotational mobility. The slots 13 and the cams 12 engaging in them are particularly in the Fig. 9 and Fig. 16 can be seen.

[0040] In corresponding implementations, the swivel device 5 has a pneumatic drive 10 for the axial actuation of the rack coupling body 9, as for example in the embodiment of 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. A corresponding pressure change in the pressure chamber 14 causes the rack coupling body 9 in the hub 2 to move axially relative to the part of the hub 2 that remains stationary, whereby the pivoting device 5 causes the vane to pivot.

[0041] In other embodiments, the swivel device 5 has a hydraulic drive 11 for axial actuation of the rack coupling body 9. Fig. Figure 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 applying the hydraulic fluid to the piston chamber 16, the rack coupling body 9 is moved axially relative to the remaining part of the hub 2, which remains stationary.

[0042] In the Fig. 1 to 23, 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 gear ring coupling is illustrated in successive stages using suitable different views of the fan wheel 1 and the other components of the reversible fan involved in the pivoting, in particular the pivoting device with its rack coupling, which comprises the blade-side partially toothed pinion bodies 5a and the hub-side gear ring body 5b, 5c.

[0043] The Fig. 1 to 4, the initial position in which the reversible 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, as mentioned above, can have a different value in the range between 0° and 90°, preferably between 0° and 50°. Fig. 1 and Fig. 2 show the fan wheel in top view and side view. Fig. 3 and Fig. 4 are sectional views showing the relevant components of the pivoting device 5, ie the blade-side partially toothed pinion bodies 5a and the hub-side gear ring bodies 5b, 5c, in the area of a fan blade 3 of the first group 3g, e.g. the fan blade 3 m , or in the area of a fan blade 3 of the second group 3u, e.g. the fan blade 3 m-1 or 3 m+1 , show.

[0044] The Fig. 5 to 8 show the reversible fan in corresponding views as the Fig. 1 to 4 after a synchronous pivoting of the first fan blade group 3g by an angle β1 of approximately 45° and an opposite synchronous pivoting of the second fan blade group 3u, ie by the angle -β1. As can be seen from the Fig. 5 and Fig. 6, the fan blades 3 of the first group 3g essentially assume their inverted position, ie they are positioned with their blade plane FE essentially parallel to the fan rotation plane UE, while the fan blades 3 of the second group 3u essentially assume their transverse position, ie they are positioned with their blade plane FE essentially perpendicular to the fan rotation plane UE. As can be seen from the Fig. 5 and Fig. 6, the fan blades 3 of the first group 3g, such as the fan blade 3 m, unhindered by the adjacent fan blades 3 of the second group 3u, such as the fan blade 3 m-1 and 3 m+1 pivot beyond their reversal position, since the fan blades 3 of the second group 3u are in or near their transverse position, in which they have the smallest extension in projection onto the fan rotation plane UE.

[0045] Out of Fig. 7 is compared to the Fig. 3 shows that the two gear ring bodies 5b, 5c have rotated slightly and the gear ring body 5b meshes with the partially toothed pinion body 5a of the fan blade 3 of the first group 3g and has rotated this pinion body 5a and thus the respective fan blade 3 by approximately 45° counterclockwise. Fig. 8 is compared with Fig. 4 shows that due to the rotation of the two gear ring bodies 5b, 5c, the gear ring body 5c meshes with the partially toothed pinion body 5a of the fan wheel 3 of the second group 3u and has thereby rotated this pinion body 5a and thus the fan blade 3 of the second group 3u by approximately 45° in the clockwise direction.

[0046] Fig. 9 shows that due to the relative rotation of the gear rim bodies 5b, 5c relative to the hub body 2a, which remains stationary, the cams 12 have moved by the corresponding angle of approximately 45° from their end position in the slots 13. Fig. 10 and Fig. 11 shows how the partially toothed pinion bodies 5a of the fan blades 3 mesh with the gear ring body 5c or the gear ring body 5b, respectively, and remain disengaged. Here, the partially toothed pinion bodies 5a of the first fan blade group 3g mesh only with the gear ring body 5b, while the partially toothed pinion bodies 5a of the second fan blade group 3u mesh only with the gear ring body 5c. The untoothed sections 7b, 8b of the partially toothed pinion bodies 5a or the gear ring body 5b ensure this functionality without causing blockages.

[0047] The Fig. 12 to 18 show the reversible fan in views corresponding to the Fig. 5 to 11 after a further rotation of the fan blades 3 by approximately 90°, i.e., after a total angle of rotation β1 of approximately 135°. Again, as during the entire pivoting movement, the fan blades 3 of the first group 3g are pivoted synchronously with one another, i.e., at the same angle 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.

[0048] From the Fig. 12 and Fig. 13 it can be seen that the fan blades 3 of the first group 3g in this position essentially assume their transverse position, ie their blade plane FE is essentially perpendicular to the fan rotation plane UE, while the fan blades 3 of the second group 3u assume their reverse position, ie their blade plane FE is essentially parallel to the fan rotation plane UE. Fig. 14, Fig. 15, Fig. 17 and Fig. 18 show that the gear ring bodies 5b, 5c, by their further rotation, rotate the partially toothed pinion bodies 5a and thus the fan blades 3 by 90° compared to the position according to the Fig. 5 to 8. As can be seen from Fig. 16, the cams 12 have rotated further by 90° in the slots 13.

[0049] As can be seen from the Fig. 12 and Fig. 13, in this position, the fan blades 3 of the second group 3u can now be pivoted beyond their reversal position unhindered 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 extension in projection onto the fan rotation plane UE is minimal. By this measure of opposing pivoting of the respective adjacent fan blades 3 m , 3 m+1Consequently, an unhindered pivoting of the fan blades 3 between their blade positions F1, F2 is achieved for the two fan operating modes, without this requiring that the fan blades 3 do not overlap in projection onto the fan circulation plane UE during normal operation of the reversible fan, in particular in the first and / or second fan operating mode. Instead, the fan blades 3 can be designed relatively freely solely according to aerodynamic and / or noise-related aspects and, in particular, can be of a shape through which adjacent fan blades 3, such as the fan blades 3 described as examples, m and 3 m+1 or 3 m-1 , in their operating position, ie for example in their first blade position F1 and / or in their second blade position F2, in projection onto the fan circulation plane UE, noticeably overlap, as is the case in the examples shown, see the Fig. 1 and Fig. 19.

[0050] The Fig. 19 to 23 illustrate the reversible fan after the fan blades 3 have been pivoted into their second blade position F2, in which the reversible fan is ready for operation in the second fan operating mode. Compared to the position according to Fig. 12 to 15 show the Fig. 19 and 21 to 23, that and how the fan blades 3 have rotated again by approximately 45°, the fan blades 3 of the same group again synchronously, the first fan blade group 3g in the opposite direction to the second fan blade group 3u. This has the consequence that all fan blades 3 now assume the same angular position of, for example, 45° to the fan 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 essentially to a point reflection of the fan blade configuration of the fan wheel 1.

[0051] Since the rotational direction of the fan impeller 1 is reversed for the operation of the reversible fan in the second fan operating mode, i.e., the fan impeller 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 functions as the leading edge for both the second and the first fan operating mode. This has the significant advantage that all fan blades 3 can be optimally designed according to aerodynamic and / or noise-reducing considerations with considerable design flexibility.

[0052] For this reason, the reversible fan can be operated with largely identical flow characteristics and performance in both the first fan operating mode and the second fan operating mode. For example, the first fan operating mode, with fan impeller 1 rotating in the direction of rotation R1, e.g., clockwise, can be a suction operation of the fan. The second fan operating mode, with fan impeller 1 rotating in the opposite direction of rotation R2, e.g., counterclockwise, can be a blowing operation of the fan.

[0053] In the case of the swivel device 5 equipped with the rack and pinion coupling, the swiveling of the fan blades 3 between their two blade positions F1, F2 proceeds in a largely similar manner as explained above for the swivel device 5 with the gear ring coupling. Fig. 25 to 32 illustrate for this example in the Fig. 3, Fig. 4, Fig. 7, Fig. 8, Fig. 14, Fig. 15, Fig. 22 and Fig. 23 analog views show the synchronous pivoting of the fan blades 3 by approximately 180° within the same group and in opposite directions between the two groups 3g, 3u.

[0054] The Fig. 25 and Fig. 26 illustrate the pivoting device with the pinion bodies 5d and the rack 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 therefrom, the rack sections 9b of adjacent fan blades 3 mesh with the pinion bodies 5d on opposite sides of the pinion bodies 5d, ie 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. the fan blade 3 m , and in Fig. 26 the rack section 9b with a right side of the pinion body 5d of a fan blade 3 of the second group 3u, e.g. the fan blade 3 m+1 .

[0055] The Fig. 27 and Fig. 28 illustrate in views analogous to the Fig. 25 or 26, the reversible fan after a rotation of the fan blades 3 by the swivel angle β1 of approximately 45° by corresponding axial movement of the rack coupling body 9 and thus of its rack sections 9b, in the Fig. 25 to 28 downwards. Since the rack section 9b in Fig. 27 on the left side of the pinion body 5d, it rotates the associated fan blade counterclockwise, while the rack section 9b in Fig. 28, which meshes with the right side of the respective pinion body 5d, the associated fan blade 3 m+1 twisted clockwise.

[0056] The Fig. 29 and Fig. 30 illustrate the situation after a further rotation of the fan blades 3 by approximately 90°, in which the rack sections 9b have moved further axially accordingly. Fig. 31 and Fig. 32 illustrate the fully pivoted end position of the fan blades 3, in which they have reached their second blade position F2. For this purpose, the rack sections 9b have moved further axially such that the fan blades 3 have been rotated a further approximately 45°, i.e., the fan blades 3 have been pivoted by an angular amount of the pivot angle of approximately 180° from their first blade position F1 to their second blade position F2.

[0057] The pivot angle β1 between the two blade positions F1, F2 for the first and second fan operating modes is approximately 180° in the examples shown, as explained, but it can also have any other value in the range from 90° to 270° depending on the application, particularly for cases in which the fan blades 3 in the two fan operating modes enclose unequal angles with their blade plane FE and the fan rotation plane UE, i.e. angle of attack. In general, the relationship β1=180°+α1-α2 results for the pivot angle β1, where α1 and α2 denote the respective angle of attack of the fan blades 3, i.e. the angle of the blade plane FE to the fan rotation plane UE, in the first and second operating modes, respectively.

[0058] As is clear from the illustrated and further embodiments explained above, the invention provides a reversible fan and an associated operating method, which enables very efficient operation of the reversible fan in each of its two operating modes, which are reversed or inverted with respect to the conveying direction M1, M2 of the medium conveyed by it, ie both in suction mode and in blowing mode. The pivoting of the fan blades 3 in such a way that adjacent fan blades 3 m , 3 m+1 opposite directions or phase-shifted in the same direction, enables an unhindered, blockage-free swiveling process even for designs in which adjacent fan blades 3 m , 3 m+1In their normal operating position in the first and / or second fan operating mode, they overlap in projection onto the fan rotation plane UE. Preferably, the pivoting of the next but one fan blades occurs synchronously; alternatively, however, a more individual pivoting of the next but one fan blades is also possible through a non-synchronous pivoting process.

[0059] The pivoting device 5 and the rotary drive 4 of the reversible fan according to the invention are configured so that in both fan operating modes, an identical side edge 6 of each fan blade 3 forms its leading edge, i.e., in both suction and blowing modes. 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 impeller 1 rotating in the opposite direction.This specific opposing or phase-shifted, co-directional pivoting of adjacent fan blades and the reversal of the rotation direction R1, R2 also have the advantage that the shape of the fan blades 3 can be optimally designed largely freely based solely on aerodynamic and / or noise-related considerations, so that good performance characteristics of the reversible fan can be achieved for both suction and blowing operation, and in both cases the same side edge 6 of each fan blade 3 functions 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 second fan operating mode.

[0060] The reversible fan according to the invention and the operating method according to the invention can be used beneficially 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, for 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

[1] Reversible 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 mounted on the hub (2) so as to be radially projecting and pivotable about a radial blade axis of rotation (FD), - a rotary drive (4) for the fan wheel (1), which is designed to drive the fan wheel (1) selectively for a first fan operating mode in a first rotational direction (R1) with a first conveying direction (M1) and for a second fan operating mode in a second rotational direction (R2) opposite to the first rotational direction (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 by , that - the pivoting device (5) is designed to pivot adjacent fan blades (3 m , 3 m+1 ) in opposite directions or out of phase in the same direction between the first wing position (F1) and the second wing position (F2). [2] Reversible fan according to claim 1, further characterized by in that the pivoting device (5) is designed to pivot a first group (3g) of fan blades (3) next but one synchronously between the first blade position (F1) and the second blade position (F2) and to pivot a second group (3u) of intermediate fan blades (3) next but one synchronously and in the opposite direction to the first group (3g) of fan blades (3) next but one between the first blade position (F1) and the second blade position (F2). [3] Reversible fan according to claim 2, further characterized by that the pivoting device (5) includes a gear ring coupling which has a partially toothed pinion body (5a) with a toothed pinion circumferential section (7a) and an untoothed pinion circumferential section (7b) on the respective fan blade (3) on the base side coaxial to the blade rotation axis (FD) and two gear ring bodies (5b, 5c) on the hub side, which are arranged axially offset parallel to the fan rotation axis (FD) and are held on a hub body (2a) with limited rotational movement relative to the hub body, between which the pinion bodies (5a) of the fan blades (3) are located and which each include toothed and untoothed sections (8a, 8b) alternating 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 two adjacent Fan blades (3 m , 3 m+1) mesh with the toothed sections (8a) of each of the gear ring bodies (5b, 5c). [4] Reversible fan according to claim 3, further characterized by 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] Reversible fan according to claim 3 or 4, further characterized by that the partially toothed pinion bodies (5a) are conical and the gear ring bodies (5b, 5c) are bevel gear-shaped. [6] Reversible fan according to claim 2, further characterized bythat the pivoting device (5) includes a rack coupling which has a pinion body (5d) on the respective fan blade (3) on the base side coaxial with the blade rotation axis (FD) and a rack coupling body (9) on the hub side, which is held axially movable on a hub body (2a) parallel to the fan rotation axis (FD), said rack coupling body having rack sections (9b) projecting axially from a peripheral region (9a), which in each case mesh with one of the pinion bodies (5d), wherein the pinion bodies (5d) of each two adjacent fan blades (3 m , 3 m+1 ) mesh in opposite directions of rotation with the respective associated rack section (9b). [7] Reversible fan according to claim 6, further characterized by that the pivoting device (5) has a pneumatic drive (10) or a hydraulic drive (11) for the axial actuation of the rack coupling body (9). [8] Reversible fan according to claim 1, further characterized byin that the pivoting device (5) is designed to pivot a first group of fan blades (3) next but one synchronously between the first blade position (F1) and the second blade position (F2) and to pivot a second group of intermediate fan blades (3) next but one synchronously and in the same direction with respect to the first group of fan blades (3) next but one between the first blade position (F1) and the second blade position (F2). [9] Reversible fan according to claim 8, further characterized by that a rotational angle offset corresponding to the phase shift between the same direction pivoting of the two groups of next but one fan blades (3) lies in a range between 60° and 120°, in particular between 80° and 100°. [10] A method for operating a reversible fan having a fan wheel (1) rotating about a fan rotation axis (LD) with a hub (2) and a plurality of fan blades (3) mounted on the hub (2) so as to project radially apart and pivot about a radial blade rotation axis (FD), in particular a reversible fan according to one of claims 1 to 9, optionally in a first fan operating mode in which the fan wheel (1) rotates in a first rotational direction (R1) with a first conveying 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 rotational direction (R2) opposite to the first rotational direction (R1) with a second conveying direction (M2) opposite to the first conveying direction (M1), and the fan blades (3) are in a second blade position (F2) different from the first, characterized bythat to switch between the first and second fan operating mode, adjacent fan blades (3 m , 3 m+1 ) are pivoted in the same direction or in opposite directions, out of phase, between the first blade position (F1) and the second blade position (F2) and the direction of rotation of the fan wheel (1) is reversed.

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