Fan Wheel

Abstract

A fan wheel having fan blades supported in a hub for pivotal movement about a longitudinal fan blade axis and a drive flange connected to the hub through a limited free-swing arrangement is provided with a planetary transmission disposed between the drive flange and the fan blades, the sun gear of the planetary transmission being connected to the drive flange for rotation therewith and the drive flange being disposed on axially opposite front sides of the fan wheel.

Description

[Technical Field]

[0001] The present invention is a fan wheel comprising fan blades supported in a hub so as to be pivotable about a longitudinal fan blade axis according to the preamble of claim 1. [Background technology]

[0002] WO 2021 / 121648 discloses a fan wheel with adjustable fan blades rotatably supported within a hub and connected via a planetary transmission with an adjustment ring. The fan wheel is driven via a drive flange that can be connected to a drive motor. The adjustment ring includes a guide track through which a guide bolt connected to the hub extends. A sun wheel of the planetary transmission is supported on the drive flange in engagement with a planet wheel supported on a control ring connected to a planet wheel carrier. To reverse the blade position, the drive speed is reduced, and as a result of inertia, the guide bolt moves in the guide track toward the opposite stop position, and the fan blade pivots to the desired angular position. The movement of the guide bolt in the guide track is slowed down by the planetary transmission. Summary of the Invention

[0003] It is an object of the present invention to provide simple design features for a fan wheel in a compact arrangement in which the fan blades are pivotally supported to avoid high stresses on the design components during the fan blade reversal procedure.

[0004] This object is achieved by the design features of claim 1. The dependent claims relate to advantageous further features.

[0005] The fan wheel according to the present invention is used, for example, in construction or agricultural machinery. It is particularly advantageous to reverse the position of the fan blades, which are supported on the hub so that they are pivotable about their longitudinal fan blade axes. When the pivotal position of the fan blades is reversed, the air movement direction of the fan wheel is reversed from an air supply mode to a fan wheel cleaning mode to remove dust and dirt deposits from the fan wheel.

[0006] The fan wheel is driven via a drive flange that can be coupled to a drive motor and is connected to the hub via a limited free-swing structure that allows adjustment of the angular position of the fan blades relative to the hub.

[0007] The fan wheel includes a planetary transmission disposed between the drive flange and the fan blades. The adjustment member driven by the planetary transmission is supported on the opposite side of the hub so that it can perform limited relative rotational movement with respect to the hub only within a free-swivel range. When the adjustment member moves relative to the hub within the limits of the free-swivel range, a desired change in the angular position of the fan blades is achieved. Each of the two extreme positions of the free-swivel range represents a stable position for the fan wheel blades. These positions are, specifically, a blowing position, which is a standard position for moving air, and an opposite-side cleaning position, which involves a reversal of the airflow direction to clean the fan wheel. In the planetary transmission, the relative rotational movement between the adjustment member and the hub within the free-swivel range for reversing the angular position of the fan blades occurs at a low speed, thereby reducing stress on the design components and, specifically, avoiding large impact forces when the extreme positions are reached.

[0008] The fan wheel can be driven in only one direction of rotation. Changing the angular position of the fan wheel blades does not require reversing the direction of rotation of the fan wheel. Rather, a change in the drive speed of the fan wheel results in relative rotational motion between the adjusting member and a hub supporting the pivotally supported fan blades due to the inertia of the fan blade wheel with the hub. As a result of this relative motion, the adjusting member changes the annular position of the fan wheel blades. For example, a speed decrease of at least a certain minimum value moves the fan wheel blades from the blowing position to the cleaning position, and a speed increase with a certain minimum acceleration value moves the fan wheel blades from the cleaning position to the blowing position.

[0009] In a fan wheel according to the present invention, the sun gear of a planetary transmission connected to and rotating with the drive flange is located on one side of the fan wheel, while the flange is located on the opposite front side of the fan wheel, such that the sun gear teeth that engage the sun gear with the planet gears are spaced axially from the drive flange.

[0010] This arrangement has the advantage that the sun gear can be formed independently of the drive flange, in particular, the gear area of ​​the sun gear is independent of the dimensions of the drive flange. The sun gear is not supported by the drive flange, but is located axially forward of the flange or on a component connected to the drive flange, which allows the use of a smaller sun gear with a correspondingly smaller number of teeth. The speed ratio of the planetary transmission can therefore be provided by the desired deceleration movement during the free-swing process, resulting in an increased adjustment torque.

[0011] The sun gear of the planetary transmission engages with planet gears supported on the planet gear carrier so that the planet gears rotate along the toothed interior of the hollow wheel. The sun gear, planet gear carrier, and hollow wheel are arranged coaxially with the drive flange, and are therefore all advantageously located opposite the drive flange and on the same axial side as the fan wheel. In this manner, the components of the planetary transmission and the drive flange can be independent of each other, allowing for greater flexibility in the design features of the fan wheel.

[0012] In an advantageous embodiment, the sun gear has a smaller outer diameter than the drive flange, which makes it possible to provide a large transmission ratio so that a high drive speed is converted into a small rotational adjustment movement of the adjustment member with a high adjustment torque.

[0013] In another advantageous embodiment, the adjusting member is formed by the planet gear carrier of the planetary transmission. This eliminates the need for a separate adjusting member and reduces the required component space. In an alternative embodiment, the adjusting member and the planet carrier can be components that are independent of each other but rotatably interconnected. The adjusting member can be in the form of an adjusting ring, for example.

[0014] According to another advantageous embodiment, the adjusting element has a gear structure and engages with a pinion arranged on the foot of a fan blade, the blade foot of which is pivotally supported in the hub, the pinion being, for example, in the form of a conical pinion. Upon rotation of the adjusting element within its free-swing range, the blade pinion rotates, causing a pivoting movement of the fan blade.

[0015] The free-swivel structure preferably comprises a guide bolt, directly or indirectly connected to rotate with the drive flange, and a curved guide path provided in the hub, through which the guide bolt extends for adjustable movement along the curved guide path. Opposite front ends of the guide path represent end positions for the fan blades, which are the blowing and cleaning positions. The guide path is advantageously in the form of a circular shaft extending over an angular portion of more than 90°, in particular more than 120°, preferably at least 150°. The relatively long length of the guide path facilitates precise adjustment of the angular position of the fan blades.

[0016] In an advantageous embodiment, two guide tracks are provided in the hub, mirror-imaged with respect to the longitudinal axis, and a guide bolt extends into each guide track, which is advantageous for providing two guide tracks to split the forces evenly to avoid torque gradients and to split the drive action.

[0017] It may be advantageous to provide a damping member at the opposite end of each guide track, which may be, for example, a rubber bumper that dampens the impact of the guide bolt at the end of the guide path during changeover from one end position to the other.

[0018] In another advantageous embodiment, the drive flange is rigidly connected to a main shaft carrying the hub. The drive flange and the main shaft are two separate, coaxially arranged components that are integrally joined but can be designed and manufactured independently. The main shaft is axially disposed between the drive flange and a sun gear of a planetary transmission that is connected to and rotates with the main shaft.

[0019] According to a further advantageous embodiment, a hollow wheel of a planetary transmission, around which the planet gears rotate, is connected to the hub and rotates therewith. The sun gear, hollow wheel and planet gears as well as the planet gear carrier are all arranged axially in front of the fan wheel at an axial distance from the drive flange. It may be advantageous to cover the gears of the planetary transmission with a transmission cover, which may be held, for example, axially outside the hollow wheel.

[0020] Further advantages and advantageous embodiments are evident from the dependent claims, the figures and the description of the drawings, in which: [Brief explanation of the drawings]

[0021] [Figure 1] FIG. 1 is a front view of a fan wheel with adjustable fan blades. [Figure 2] FIG. 2 is a cross-sectional view of the fan wheel taken along line II-II in FIG. [Figure 3] FIG. 3 is an enlarged view of the cross-sectional view of FIG. 2. [Figure 4] 4 is a cross-sectional view of the hub taken along line IV-IV in FIG. 3, perpendicular to the longitudinal drive shaft axis of the fan wheel. DETAILED DESCRIPTION OF THE INVENTION

[0022] In the drawings, identical components are designated by identical reference numerals.

[0023] The fan wheel 1 can be driven to rotate about a longitudinal axis 2 (Figs. 2 and 3), which also serves as a drive shaft. The fan wheel includes fan blades 3 distributed circumferentially and extending radially from the longitudinal axis 2. The fan blades 3 are pivotally supported on a hub 4 so as to be pivotable, specifically by nearly 180°, about the longitudinal axis 5 between two end positions corresponding to a blowing mode and a cleaning mode. The blade position corresponding to the blowing mode represents the standard position in which airflow is generated by the rotating fan wheel 1. The fan blades 3 briefly assume the cleaning mode position to reverse the fan's airflow direction and remove dust and dirt from the fan blades.

[0024] The fan wheel 1 further comprises a drive flange 6, a main shaft 7, a sun gear 9, planetary gears 10 supported on a planetary gear carrier 11, and a planetary transmission 8 with a hollow wheel 12. These components are arranged coaxially with respect to the longitudinal drive shaft 2, i.e., rotate about the longitudinal drive shaft 2 with respect to the planetary gears 10. The drive flange 6 is driven by a drive device, in particular an electric or hydraulic motor. The drive motor operates in only one direction of rotation. Furthermore, the direction of rotation of the fan wheel does not change when changing from blowing mode to cleaning mode.

[0025] The drive flange 6 has a hollow cylindrical flange section for connecting to the drive unit. Adjacent to the hollow cylindrical flange section is a shoulder ring with a relatively large radial extension, which is connected to the main shaft 7 by a connecting screw 13 and rotates together with the main shaft 7. The main shaft 7 supports the hub 4, resting radially outside the main shaft 7, so that the hub 4 can rotate relative to the main shaft 7 and the drive flange 6 within the limits of a free-swivel arrangement. The free-swivel arrangement is formed by a guide bolt 14 and an arcuate guide track 15, which is arranged in the hub 4 concentrically with the longitudinal drive shaft 2 (FIGS. 3 and 4) and extends over an angular section of approximately 180°. To distribute forces evenly, the hub 4 has two guide tracks 15, mirror-imaged with respect to the longitudinal drive shaft 2, each with a guide bolt 14 extending therethrough. At both ends of each guide track 15 are rubber shock absorbers 16, which damp the impact of the guide bolts 14 during adjustment between the air transfer mode and the cleaning mode.

[0026] The drive flange 6 and the planetary transmission 8 are arranged on axially opposite sides of the main shaft 7. A sun gear 9 of the planetary transmission 8 is connected to and rotates with the main shaft 7, as well as to and rotates with the drive flange 6. The gear structure of the sun gear 9 is axially spaced apart from the main shaft 7 and, consequently, from the drive flange 6. The sun gear 9 has a smaller outer diameter than the drive flange 6 in the region of the hollow cylindrical flange portion and also of the shoulder ring.

[0027] The sun gear 9 engages with planet gears 10 of a planet gear carrier, which is rotatably supported on a shoulder of the main shaft 7. The planet gears 10 are engaged radially outward with an internal gear structure of a hollow wheel 12 that abuts the hub 4 and is connected to it for rotation therewith. The planet gear carrier 11 forms an annular control member for angular adjustment of the fan blades 3. For this purpose, on the side facing the drive flange 6, the planet gear carrier 11 is provided with a side gear structure 17, in particular a conical gear structure that engages with a conical pinion 18 located radially inward of a shaft foot 19 of each fan blade. The shaft foot 19 is rotatably supported in the hub 4 and facilitates rotation of the fan blades 3 about the longitudinal blade axis 5.

[0028] When adjusting the fan blades 3 from blowing mode to cleaning mode, the drive speed of the fan wheel 1 is reduced to provide a certain minimum speed reduction. Due to inertia, the fan blades 3 try to maintain their original speed which results in relative motion between the drive flange 6 or, respectively, the main shaft 7 and the hub 4. As a result, the guide bolts 14 connected to the main shaft 7 move in guide tracks 15 formed in the hub 4 towards their opposite stop positions. The relative motion between the drive flange 6 or the main shaft 7 results in a change in the angular position of the fan blades 3 about their respective blade longitudinal axes 5 without reversing the direction of rotation of the fan wheel 1.

[0029] The adjustment of the fan blades 3 about their longitudinal blade axes 5 is not effected in sudden bursts, but rather by coupling with the planetary transmission 8 at a reduced speed that depends on the planetary transmission's transmission ratio. As a result of the rigid coupling of the sun gear 9 with the main shaft 7 and the drive flange 6, the reduction in drive speed directly affects the sun gear 9 as well as the other gears of the planetary transmission 8. As a result, the planet carrier 11 with its gear structure 17 rotates relative to the blade pinion 18 and shaft foot 19, causing the fan blades 3 to rotate about their longitudinal blade axes.

[0030] When adjusting the fan blades 3 in the opposite direction, i.e., from the washing mode to the blowing mode, the drive speed of the fan wheel 1 increases to reach a minimum deceleration value. Even during this adjusting movement, the fan blades 3 tend to maintain their original speed due to inertial forces that again bring about a relative movement between the drive flange 6 or, respectively, the main shaft 7 and the hub 4, causing the guide bolts 14 to move in the guide tracks 15 towards their original, opposite position. The fan blades 3 move again to their original position corresponding to the blowing mode, the adjusting movement of the fan blades 3 now also resulting from the coupling with the planetary transmission 8 at low speed.

Claims

1. A fan wheel (1) comprising fan blades (3) supported in a hub (4) so ​​as to be pivotable about a longitudinal blade axis (5), the fan wheel (1) comprising a drive flange (6) connected to the hub (4) through a limited free-swivel arrangement, a planetary transmission (8) arranged between the drive flange (6) and the fan blades (3), a control member of a planetary gear carrier (11) driven by the planetary transmission (8) supported on the opposite side of the hub (4) so ​​as to be rotatable within a limited free-swivel range relative to the hub (4) independent of the rotational drive movement, The sun gear (9) of the planetary transmission (8) connected to the drive flange (6) and rotating together with the drive flange (6) are arranged on opposite axial sides of the fan wheel (1) in front of the fan wheel (1), and an engagement structure for engaging the sun gear (9) with the planetary gears (10) of the planetary transmission (8) is spaced axially from the drive flange (6).

2. 2. A fan wheel according to claim 1, characterized in that the sun gear (9) has a smaller outer diameter than the drive flange (6).

3. 3. A fan wheel according to claim 1 or 2, characterized in that the planet gear carrier forms an adjusting member (11) of the planetary transmission.

4. 4. A fan wheel according to claim 1, wherein the adjusting member (11) comprises a gear structure (17) engaging with a blade pinion (18) arranged on a shaft foot (19) of the fan blade (3).

5. 5. A fan wheel according to claim 1, wherein a free-swivel structure is formed by a guide bolt (14) connected to the drive flange (6) and rotating therewith, and wherein an arcuate guide track (15) is provided in the hub (4), and the guide bolt (14) extends into the guide track (15).

6. 6. A fan wheel according to claim 5, characterized in that the guide track (15) in the hub (4) extends over an angular portion of more than 90°, in particular more than 120°, preferably at least 150°.

7. 7. A fan wheel according to claim 5 or 6, characterized in that damping members (16) are arranged at both ends of the guide track (15).

8. 8. A fan wheel according to any one of claims 5 to 7, characterized in that the hub (4) comprises two guide tracks (15) arranged in mirror image with respect to the longitudinal blade axis (5), and a guide bolt (14) extends into each guide track (15).

9. A fan wheel according to any one of claims 1 to 8, characterized in that the drive flange (6) is connected to and rotates with a main shaft (7), the main shaft supporting the hub (4).

10. 10. A fan wheel according to claim 9, characterized in that the sun gear (9) abuts axially on and is connected to the main shaft (7).

11. A fan wheel according to any one of claims 1 to 10, characterized in that the hollow wheel (12) of the planetary transmission (8) in which the planetary gears (10) are housed is connected to the hub (4) so ​​as to rotate together.

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