FAN WHEEL WITH REINFORCEMENT RING

Description

[0001] The invention relates to a fan wheel of a blower with a reinforcing ring.

[0002] Types of fan wheels for blowers or fans are known from the prior art in a multitude of variants, for example as axial, radial or diagonal impellers with a base plate on which a plurality of fan wheel blades are arranged, and optionally a cover plate covering the fan wheel blades.

[0003] Printed prior art in the present technical field is disclosed, for example, in documents US2005 / 106024 A1, US 4,762,465 A and WO 2020 / 143241 A1.

[0004] Due to the high operating speed, the strength of fan wheels of this type is of crucial importance. The area where the base plate meets the fan blades is particularly critical under heavy loads.

[0005] The invention is therefore based on the objective of providing a fan wheel with increased strength, particularly in this critical area.

[0006] This problem is solved by the combination of features according to claim 1.

[0007] According to the invention, a fan wheel is proposed with at least one base disk and a plurality of fan blades formed around an axis of rotation of the fan wheel. These blades extend axially from the base disk and, together with the base disk, form a flow channel between each other. A reinforcing ring is arranged within the base disk, having a plurality of axial projections that extend axially into the fan blades, thereby reinforcing both the base disk and the fan blades. The axial projections of the reinforcing ring have at least one nipple projecting from the inner and outer wall surfaces of the respective axial projection, which engages with the fan wheel body of the fan blades.

[0008] The specially designed reinforcing ring, featuring axial projections, is integrated into the base plate. These projections extend axially parallel to the impeller's axis of rotation, allowing the impeller blades to enclose them. This increases both local and overall impeller strength, enabling higher load capacities. Furthermore, the choice of impeller material becomes more flexible. The use of the reinforcing ring allows for the use of more cost-effective materials for the impeller body, which still meet the technical requirements. This also increases design freedom in critical areas, such as the impeller blade design and the transition between the base plate and the impeller blades.The geometric design of the reinforcement ring is also variable and can be adapted to the different stresses in the respective operation. For example, the reinforcement ring required for each fan wheel can be selected from a set of reinforcement rings.

[0009] Particularly with plastic fan impellers, the required strength is achieved. Simultaneously, the material provides high corrosion resistance. Therefore, in a favorable fan impeller design, the reinforcing ring is made of a material with a higher strength than the impeller body. The preferred material combination is plastic for the impeller and metal for the reinforcing ring.

[0010] A further advantage is an embodiment of the fan wheel in which the geometric shape of the axial projections corresponds to the geometric shape of the fan blades, with the fan blades completely enclosing the axial projections. The fan blades can have various configurations, for example, straight, forward-curved, or backward-curved. The axial projections are preferably formed in the same shape and reinforce the fan blades not only at specific points but at least section by section along their entire length.

[0011] A particularly advantageous design of the fan impellers is one in which the axial projections within the fan blades extend over at least 30%, more preferably at least 50%, and more preferably at least 70% of the total extent of the fan blades from a radial inner to a radial outer surface of the fan impeller. The reinforcing effect increases the greater the overlap between the fan blades and the axial projections in their respective extents.

[0012] In principle, it is advantageous if the axial projections extend a midpoint of the total extent of the fan blades from the radial inside to the radial outside of the fan wheel.

[0013] Furthermore, an advantageous embodiment of the fan wheel provides that the axial projections within the fan blades extend over at least 10%, more preferably at least 20%, and more preferably at least 30% of the total axial extent of the fan blades extending from the base disk. The axial extent runs parallel to the axis of rotation. Even a small axial extent has a positive effect, since the critical transition area from the base disk to the fan blades is reinforced by the reinforcing ring. A longer axial extent of the axial projections reinforces the fan blades in particular and thus the entire fan wheel.

[0014] In a further development, the fan wheel is characterized by the fact that the reinforcing ring is designed as a single, closed ring. This reinforces the entire base plate across its entire circumference.

[0015] A favorable design also features a reinforcement ring with numerous holes arranged in a pattern. These holes reduce the amount of material required and thus the weight of the reinforcement ring. This, in turn, reduces the mass of the fan wheel and the forces acting upon it during operation. Furthermore, the holes improve the connection to the fan wheel body.

[0016] A further development of the fan wheel is characterized by a hole pattern designed such that radially adjacent holes are offset from each other in the circumferential direction. With round holes, these can be arranged closer together. Furthermore, the material weakening caused by each hole does not overlap. Despite the large number of holes, the reinforcing ring as a whole remains stable with such a hole pattern. The total cross-sectional area of ​​the holes in the reinforcing ring is preferably over 50%, and particularly over 75%, of the area of ​​the reinforcing ring. An alternative hole shape is characterized by hexagons, and the hole pattern is particularly characterized by a honeycomb pattern.

[0017] Another advantageous embodiment of the fan wheel provides that the reinforcing ring has locally limited radial extensions in the circumferential direction. These radial extensions project locally beyond the annular shape of the outer circumferential edge of the fan wheel and locally increase the ring area by radially increasing the extent of the reinforcing ring.

[0018] A particularly advantageous embodiment of the fan wheel is characterized in that the respective radial extensions are provided in an area of ​​the reinforcing ring in which the axial projections are formed. InIn other words, the radial extensions and axial projections lie in a radial plane defined by the fan wheel's axis of rotation. The reinforcing ring therefore has an increased surface area and material accumulation precisely in the region where the axial projections are located, thus increasing its strength.

[0019] In a particular design of the fan wheel, the axial projections are positioned off-center relative to the radial extensions when viewed in the circumferential direction. Due to the rotation of the fan wheel during operation, the load on the leading and trailing edges of the fan blades differs. This results in different loads in the critical area of ​​the transition to the base plate. The off-center positioning addresses this issue and enables a significant increase in strength, which has a positive effect on operation, i.e., the rotation of the fan wheel.

[0020] In a further development, the radial extensions each feature two specially designed circumferential edge sections. These circumferential edge sections are designed to have different angles relative to a tangent applied to the outer edge of the reinforcement ring. These different angles also account for the fact that the load varies depending on the direction of rotation of the fan wheel. A particularly advantageous design is one in which the angles are adapted to the inclination angle of the fan blades relative to the axis of rotation. For example, with backward-curved fan blades, the inclination angle is adjusted in the same backward direction, so that one of the circumferential edge sections and the fan blades are aligned, particularly extending radially outward in parallel or substantially parallel directions.

[0021] Other advantageous embodiments of the invention are characterized in the dependent claims or are described in more detail below together with the description of the preferred embodiment of the invention with reference to the figures. The figures show: Fig. 1 a first sectional view of a partial section of a fan wheel according to the invention; Fig. 2 a second sectional view of the fan wheel made of Figure 1 , Fig. 3 a perspective view of the reinforcement ring of the fan wheel made of Figure 1 .

[0022] The Figure 1 and 2 They show an exemplary embodiment of a fan wheel 1 in sectional views, wherein in Figure 1For a better understanding of the invention, the hidden edges are also shown. The fan wheel 1 is formed from a base plate 2, a cover plate 3, and several fan blades 4 arranged around the axis of rotation RA. These blades extend axially between the base plate 2 and the cover plate 3, each forming a flow channel between them. The fan blades 4 are shown curved, but can also be, for example, straight. The base plate 2 transitions on its radial inner surface, facing the axis of rotation RA, into a receptacle 5 for connecting a drive for the fan wheel 1. The cover plate 3, the base plate 2, and the fan blades 4 form the fan wheel body and are manufactured in one piece from plastic using a casting process, in particular an injection molding process.The reinforcing ring 6 is arranged within the base plate 2, which is preferably made of metal and is incorporated by casting, in particular by injection molding.

[0023] The reinforcement ring 6 is available individually in Figure 3The reinforcement ring 6 is shown. It is designed as a single-piece closed ring with a flat annular body 77, which has several identically shaped radial extensions 8 distributed around its circumference. In the region of the radial extensions 8, the area of ​​the annular body 77 is locally enlarged. Each of the radial extensions 8 forms two circumferential edge sections 9, 9', where the overall radius of the reinforcement ring 6 increases. In the embodiment shown, the circumferential edge sections 9, 9' each have different angles α and β relative to a tangent applied to the outer edge of the reinforcement ring 6, where α < β. The angles α and β are adapted to the respective inclination angle of the impeller blades 4 relative to the axis of rotation RA, i.e., the angles can be different if the curvature of the impeller blades 4 changes.The course of the radial extensions 8 between the two circumferential edge sections 9, 9' corresponds to that of the remaining ring body 77 between the radial extensions 8.

[0024] Furthermore, several axial projections 7 extend from the surface of the ring body 77 in the axial direction. The axial projections 7 are curved circumferentially in the same way as the fan blades 4. As in Figure 1 The axial projections 7 can be clearly seen extending in an axial direction into the fan blades 4. Figure 2Figure 1 shows that the geometric shape of the axial projections 7 corresponds to the geometric shape of the fan blades 4 and that the fan blades 4 completely enclose the axial projections 7. On the annular body 77 of the reinforcing ring 7, the axial projections 7 and the radial extensions 8 are provided in the same circumferential section. Viewed in projection, each axial projection 7 overlaps the respective circumferential edge section 9'. The axial projections 7 are therefore formed eccentrically relative to the radial extensions 8 when viewed circumferentially. According to the invention, each axial projection 7 has at least one nipple 21 projecting from the inner and outer wall surfaces of the respective axial projection 7, which engages with the fan body of the fan blades 4.

[0025] The ring body 77 of the reinforcing ring 6 has a plurality of hexagonal holes 10 distributed around its entire circumference. These holes are positioned in a hole pattern such that radially adjacent holes 10 are offset from each other circumferentially with respect to their respective centers. This results in a honeycomb structure of the holes 10. It is also possible, and covered by the disclosure, that the holes 10 are arranged partially overlapping each other on the ring body 77 when viewed radially. The radial extensions 8 are free of holes 10.

[0026] Referring to the Figure 1 and 2The size of the axial projections 7 in relation to the impeller blades 4 is also shown. In the embodiment shown, the axial projections 7 extend within the impeller blades 4 over a length L of 60% of the total extent S of the impeller blades 4 from the radial inner side to a radial outer side of the impeller 1. The axial projections 7 are positioned centrally within the impeller blades 4 and thus also extend beyond the center of their total extent, see in particular [reference]. Figure 2 In the axial direction, the axial projections 7 extend along the axis of rotation RA within the fan blades 4 over at least 15% of the total axial extent H of the fan blades 4, see Figure 1 .

[0027] The invention is not limited in its implementation to the preferred embodiment described above. Rather, it encompasses a number of variants. However, the scope of protection of the invention is defined only by the following claims.

Claims

1. A fan wheel (1) comprising at least one base disk (2) and a plurality of fan wheel blades (4) arranged about an axis of rotation (RA) of the fan wheel (1) that extend in an axial direction from the base disk (2) and each form a flow channel between them together with the base disk (2), wherein a reinforcing ring (6) is arranged within the base disk (2), said reinforcing ring having a plurality of axial protrusions (7) which extend in the axial direction into the fan wheel blades (4) and thereby reinforce both the base disk (2) and the fan wheel blades (4), characterized in that the axial protrusions (7) of the reinforcing ring (6) comprise at least one nipple (21) projecting relative to inner and outer wall surfaces of the respective axial protrusion (7), said nipple being in engagement with the fan wheel body of the fan wheel blades (4).

2. The fan wheel according to Claim 1, characterized in that the reinforcing ring (6) is formed from a material whose strength is higher than that of the material of the fan wheel body defining the fan wheel (1).

3. The fan wheel according to Claim 1 or 2, characterized in that a geometric shape of the axial protrusions (7) corresponds to a geometric shape of the fan wheel blades (4), wherein the fan wheel blades (4) completely enclose the axial protrusions (7).

4. The fan wheel according to any one of the preceding claims, characterized in that the axial protrusions (7) extend within the fan wheel blades (4) over at least 50% of a total extent of the fan wheel blades (4) from a radial inner side to a radial outer side of the fan wheel (1).

5. The fan wheel according to the preceding claim, characterized in that the axial protrusions (7) extend beyond a midpoint of the total extent of the fan wheel blades (4).

6. The fan wheel according to any one of the preceding claims, characterized in that the axial protrusions (7) extend within the fan wheel blades (4) over at least 10% of a total axial extent of the fan wheel blades (4).

7. The fan wheel according to any one of the preceding claims, characterized in that the reinforcing ring (6) is formed as a one-piece closed ring.

8. The fan wheel according to any one of the preceding claims, characterized in that the reinforcing ring (6) comprises a plurality of holes (10) arranged in a hole pattern.

9. The fan wheel according to the preceding claim, characterized in that the hole pattern is configured such that radially adjacent holes (10) are positioned offset from one another in the circumferential direction relative to their respective centers.

10. The fan wheel according to any one of the preceding claims, characterized in that the reinforcing ring (6) comprises radial extensions (8) which are locally limited in the circumferential direction.

11. The fan wheel according to the preceding claim, characterized in that the radial extensions (8) are provided in a region of the reinforcing ring (6) in which the axial protrusions (7) are formed.

12. The fan wheel according to the preceding claim, characterized in that the axial protrusions (7), as viewed in the circumferential direction, are formed eccentrically with respect to the radial extensions (8).

13. The fan wheel according to any one of Claims 10 to 12, characterized in that the radial extensions (8) each comprise two circumferential edge sections (9, 9') which have different angles (α, β) relative to a tangent applied at the outer edge of the reinforcing ring (6).

14. The fan wheel according to the preceding claim, characterized in that the angles are adapted to inclination angles of the fan wheel blades (4) relative to the axis of rotation (RA).