Support cage for a fan, fan, heat pump and method for producing a support cage

Abstract

The invention relates to a support cage for a fan, in particular for use in or with a heat pump. Another aspect of the invention relates to a fan having such a support cage. Another aspect of the invention relates to a heat pump having a fan and such a support cage. Another aspect of the invention relates to a method for producing such a support cage. The support cage (1) comprises a cage structure (2, 3, 4) with a motor fastening means (4) and is made of plastic.

Description

[0001] Support basket for a fan, fan, heat pump and method for producing a support basket

[0002] The invention relates to a carrying basket for a fan, in particular for use in or with a heat pump.

[0003] A further aspect of the invention relates to a fan with such a carrying basket.

[0004] A further aspect of the invention relates to a heat pump with a fan and such a carrying basket.

[0005] A further aspect of the invention relates to a method for producing a corresponding carrying basket.

[0006] Support devices of the type in question, particularly for use in or with heat pumps, have been known in practice for years. Heat pumps are subject to strict noise specifications, as they are used primarily in residential areas, i.e. in noise-sensitive environments. Low noise levels and good acoustic data are therefore preferred by customers of fan systems for heat pumps. In previous approaches, such as those known from DE 2 2 397 B4, support devices are usually made of metal, as metal enables a stable construction with low flow resistance. In addition, the use of welding devices enables cost-effective adaptation to different applications or customer devices and the production of small series. However, the manufacture of support devices from metal wires is comparatively complex.Due to the high demand for heat pumps, and thus also for corresponding fans and support devices, cost reductions in the production of corresponding support devices offer a significant competitive advantage.

[0007] The present invention is therefore based on the object of designing and developing a support device of the type mentioned above in such a way that cost reductions in the production of the support device can be achieved. A further object is to provide a support device with further improved acoustic properties. The support device should also be distinguished from competitive products.

[0008] According to the invention, the above object is achieved by the features of the independent claims. Accordingly, the support device in question is a support basket for a fan, in particular for use in a heat pump. The support basket comprises a basket structure with a motor mount. Furthermore, the support basket is made of plastic.

[0009] In accordance with the invention, it was initially recognized that implementing the support basket in plastic offers great potential for cost reduction. With higher unit volumes, as achieved in the manufacture of heat pumps, the production of support devices from plastic becomes economically feasible because the high setup and tool costs for the necessary injection molding tool are spread over the larger number of manufactured units. By using a basket structure with a motor mount, a similar level of stability can be achieved as when using a metal support grid, thereby compensating for the inherently lower stability of plastic. The stability of the support device can be achieved via the geometry of the basket structure used as well as the cross-sections of the structural elements of the basket structure and motor mount used.

[0010] To achieve the necessary stability with a low section modulus, the cage structure can comprise radial support struts and circular struts that are connected to each other. The circular struts intersect the support struts. This design provides the necessary stability to accommodate the fan while still allowing for low air resistance, which is beneficial for acoustics.

[0011] In particular, the support struts can terminate in the motor mount at the radial center of the support cage. This provides the necessary stability to the motor mount, to which the fan is attached. Furthermore, some of the support struts can terminate radially outward into mounting structures for attaching the support cage, such as to a heat pump housing or a nozzle. This allows the support cage to be attached to the heat pump without the need for additional radial struts or mountings.

[0012] Advantageously, at least one, but in particular each, of the annular struts can have an oval shape, so that the thickness of the at least one annular strut increases to a maximum in the upstream direction and decreases again in the downstream direction. This allows for lower resistance in the center of the strut, even with a larger diameter of the struts, and thus favorable acoustics.

[0013] For example, a first average thickness of the support struts in the airflow direction can be at least as large as a second average thickness of the support struts orthogonal to the airflow direction. In particular, the first average thickness can be larger, such as at least 10% larger (or at least 20% larger, or at least 50% larger, or at least twice as large) than the second average thickness. By combining a profile that is as narrow as possible but high, with the annular struts, sufficiently high stability with low resistance can be achieved.

[0014] Advantageously, the peripheral side wall of the basket structure can essentially have the shape of a truncated cone with openings. Such a shape has the advantage that the support basket can be manufactured using an injection mold that can be opened in a single direction (axially) without the use of a slide. This allows the costs of the injection mold to be kept as low as possible.

[0015] For example, sections of the circumferential side wall may have an angle of at least 0.5° (or at least 1°, or at least 2°, or at least 3°, or at least 4°, or at least 5°, or at least 6°) relative to an axis of the truncated cone. For example, the angle in the interior of the circumferential side wall of the truncated cone shape may be formed by a geometry of the support struts of the basket structure. This enables production using the injection molding tool as described above.

[0016] Advantageously, the circumferential side wall can be divided into at least two sections. The at least two sections can each be delimited by a radially extending support strut. The at least two sections of the side wall can each have an angle of 0.5° (or at least 1°, or at least 2°, or at least 3°, or at least 4°, or at least 5°, or at least 6°) with the axis of the truncated cone. The division into two sections supports production using the injection mold, since the two sections can each be formed by one of the halves of the injection mold.

[0017] The carrying basket can advantageously be constructed in one piece. This one-piece construction can significantly reduce costs.

[0018] In particular, the carrying basket can be manufactured using an injection molding process, as previously mentioned. This enables cost reductions, especially for large volumes and low manufacturing complexity.

[0019] The support cage features a motor mount, thus acting as a motor mount for the fan motor. To provide power and control for the fan, control and power supply cables are fed to the motor. The support cage can feature an integrated cable guide or cable mount. This facilitates the attachment and routing of the respective cables between the fan motor and, for example, a heat pump control unit.

[0020] The support basket can, but does not have to, provide protection against contact with the fan, for example. In one variant, the support basket can be designed as a contact guard. This can be achieved by keeping the distance between the annular struts, and optionally the radial support struts, so small that the support basket satisfies the relevant safety regulations for contact protection. This enables the manufacture of a ready-to-use support basket with contact protection in a single production step, but increases the complexity of the injection molding tool. Alternatively, the support basket can have a receiving structure for a separate contact guard, via which the separate contact guard can be detachably or permanently attached to the support basket.In this case, an additional manufacturing step is required to produce the separate contact guard from wire or using an additional injection mold, and an additional manufacturing step is required to attach the contact guard. In return, the injection mold for producing the carrying basket can be less complex.

[0021] The same applies if a flow straightener is provided. For example, the support basket can be designed as a flow straightener in one variant. This enables the production of a support basket with flow straightener in a single production step, but increases the complexity of the injection mold. Alternatively, the support basket can have a receiving structure for a separate flow straightener, via which the separate flow straightener can be detachably or permanently attached to the support basket. In this case, an additional production step is required to produce the separate flow straightener and an additional production step to attach the flow straightener. In return, the injection mold for the support basket can be less complex.

[0022] A further aspect of the present invention relates to a fan, in particular an axial fan, with a support basket according to the invention. In particular, the fan can have an external rotor motor. Such an external rotor motor is highly efficient and can be operated quietly.

[0023] The invention also relates to a heat pump with a fan, in particular an axial fan, and a support basket according to the invention. The fan is attached to the motor mount of the support basket. The support basket acts as a motor mount for the fan motor.

[0024] Finally, the invention relates to a method for producing such a carrying basket. The method comprises providing an injection mold for manufacturing the carrying basket. The method comprises injection molding the carrying basket using the injection mold. The carrying basket comprises a basket structure with a motor mount and is made of plastic. The injection mold can be opened in a single direction and without the use of a slide. This enables cost-effective production of the carrying basket in high volumes.

[0025] In some cases, as previously described, the support basket can be combined with a separate touch guard. Thus, the method can further comprise providing the separate touch guard and attaching the separate touch guard to a receiving structure for the separate touch guard on the support basket. The use of a separate touch guard reduces the complexity of the injection molding tool.

[0026] In addition, the method may further comprise providing a separate flow straightener and attaching the separate flow straightener to a support structure for the separate flow straightener on the support basket. Here, too, the use of a separate flow straightener reduces the complexity of the injection molding tool.

[0027] There are now various possibilities for advantageously embodying and developing the teaching of the present invention. For this purpose, reference is made, on the one hand, to the claims subordinate to the independent claims and, on the other hand, to the following explanation of preferred embodiments of the invention with reference to the drawings. In conjunction with the explanation of the preferred embodiments of the invention with reference to the drawings, generally preferred embodiments and developments of the teaching are also explained. The drawings show:

[0028] Fig. 1 is an isometric view of an inventive

[0029] carrying basket;

[0030] Fig. 2a and 2b the carrying basket from the front and from the rear respectively;

[0031] Fig. 3a, 3b, and 3c show supporting struts and annular struts of a basket structure of the supporting basket; Fig. 4a shows a definition of the height and width of a strut;

[0032] Fig. 4b and 4c possible orientations of ring-shaped struts of the basket structure of the carrying basket;

[0033] Fig. 5a and 5b the carrying basket from the side;

[0034] Fig. 6a to 6d show a fan with a carrying basket according to the invention;

[0035] Fig. 7a and 7b show a heat pump with a fan with a carrying basket according to the invention;

[0036] Fig. 8a and 8b a demoulding concept for the carrying basket;

[0037] Fig. 9a to 9d a carrying basket with an integrated contact protection; and

[0038] Fig. 10 to 10d a carrying basket with a separate contact protection.

[0039] The present invention relates to a support device in the form of a flow-optimized plastic support basket for heat pump applications. Figures 1 to 10d show various details of the support basket. Figure 1 shows an isometric view of a support basket according to the invention, and Figures 2a and 2b show the support basket from the front and rear, respectively. Figures 3a to 4c show details of the support basket struts. Figures 5a and 5b, in turn, show the support basket from the side.

[0040] 1 to 10d, the support basket, which will also be referred to as the support basket below, comprises a basket structure 2, 3 with a motor fastening 4. The support basket thus acts as a motor suspension for a motor of a fan. In the exemplary embodiments in FIGS. 1 to 10d, the basket structure comprises a plurality of radially running support struts 2 and a plurality of annular struts 3. The annular struts cross the support struts. In the examples in FIGS. 1 to 8b and 10a to 10d, the basket structure comprises eight radially running support struts 2 and six annular struts 3. Each annular strut crosses each support strut, so that partial sections of the annular struts run between the support struts 2.However, the exact number of struts depends on many factors, such as the required stability, the strut profiles, and whether the support cage is intended to serve as contact protection (or whether a separate contact protection is to be used). For example, Figs. 9a to 9d show an example with a larger number of circumferential struts, whereby the support cage also serves as contact protection. For example, a number of three support struts can be assumed as a lower limit.

[0041] As also shown in the figures, the support struts 2 open into the motor mounting 4 in the radial center of the support basket. On the opposite side, i.e. radially outward, at least some of the support struts can further have a mounting structure 5 (also called a customer interface), such as a bulge with a hole, for mounting to another component, such as a housing of the heat pump. In other words, at least some of the support struts 2 open radially outwards into mounting structures 5 for mounting the support basket to the heat pump, such as a housing of the heat pump or a nozzle. In the figures, this is the case for four of the eight support struts 2. Here, too, a number of three support struts 2 with mounting structures 5 can be assumed as the lower limit.

[0042] Due to the low elastic modulus (stiffness factor) of plastics compared to steel (steel 210,000 MPa / reinforced plastic approx. 9,000 MPa), stability is achieved through the supporting structure or the cross-sections (section modulus). Larger strut cross-sections lead to flow losses. Separation at the struts of the support cage and the interaction of separation vortices with the impeller leading edge lead to increased noise.

[0043] The invention solves these problems by creating a cost-effective engine mount made of reinforced plastic with flow-optimized support struts. The use of increased cross-sections of the support struts with flow-optimized struts offers sufficient stability and at the same time improves the acoustics compared to existing support baskets or wire grids made of circular steel wire. Figs. 3a, 3b and 3c show the support struts 2 and the annular struts 3 of the basket structure of the support basket 1. In particular, an example cross-section of the support struts 2 and the flow-optimized annular struts 3 is visible there. In Fig. 3a, the profiles of the support struts are particularly highlighted. Fig. 3b, in contrast, shows the geometry of the annular struts and Fig. 3c shows their orientation relative to the air flow direction.The geometry of the support struts is designed to have, on the one hand, high stability and, on the other hand, low flow resistance. This can be achieved by ensuring that the thickness d of the support struts is at most as large as the height h of the profile of the support struts, i.e., d / h < 1. Fig. 4a shows how the two variables d and h of the respective struts are to be interpreted. In other words, a first average thickness (the height h) of the support struts 2 (i.e., the profile of the support struts) in the air flow direction can be at least as large as a second average thickness of the support struts (the thickness d) orthogonal to the air flow direction. Advantageously, as shown in Figs. 3a to 3c, the first average thickness can be larger, for example at least 10% larger (or at least 20% larger, or at least 50% larger, or at least twice as large) than the second average thickness.

[0044] Advantageously, the basket structure also has flow-optimized, circumferential struts. Here, too, a first average thickness (the height h) of the annular circumferential struts 3 (i.e. the profile of the support struts) in the air flow direction can be at least as great as a second average thickness of the annular circumferential struts 3 (the thickness d) orthogonal to the air flow direction. Advantageously, as shown in Figs. 3b and 3c, the first average thickness can be greater, for example at least 10% greater (or at least 20% greater, or at least 50% greater, or at least twice as great) than the second average thickness. In order to reduce air resistance, the wall thickness of the circumferential struts can increase in the upstream direction, have its maximum in the middle region of the height h and decrease again in the downstream direction.In other words, at least one (and preferably each or almost each) of the annular struts 3 can have an oval shape, so that the thickness of the at least one annular strut increases to a maximum in the upstream direction and decreases again in the downstream direction. Such a profile with a thickness that increases to a maximum in the upstream direction and decreases in the downstream direction can also be used for the support struts.

[0045] The orientation and arrangement of the flow-optimized, circumferential struts 3 is also important. This is shown in Fig. 4b and 4c. Fig. 4b and 4c show possible orientations of annular, circumferential struts of the basket structure of the support basket. The orientation of the circumferential struts 3 is ideally aligned at an angle a = 90° to the skeleton line 6 (also profile center line, shown in Fig. 4c) of the support struts 2. However, the orientation can basically range from 45° to 135° to the skeleton line 6. In other words, the annular, circumferential struts can each be aligned at an angle between 45° and 135°, but preferably at approximately 90° (+- 5°), to the skeleton line 6 of the support struts 2.

[0046] In Fig. 5a and 5b, the profiles and orientation of the circumferential struts 3 are highlighted again in a side view.

[0047] The support basket according to the invention is a support basket for a fan, in particular a support basket for a fan for a heat pump. Figs. 6a to 6d show the support basket as part of a fan 7. Figs. 6a and 6b show two isometric views of the fan 7 with the support basket 1-5, a motor 8 attached to the motor mount 4, and an impeller 9 with impeller blades. The motor can be an external rotor motor, for example. Figs. 6c and 6d show the fan 7 from the front and rear, respectively.

[0048] Figs. 7a and 7b again show the integration of the fan 7 (with motor 8 and impeller 9) with support basket 1 into a heat pump, represented by the heat pump housing 10. Fig. 7a shows an isometric view, and Fig. 7b a frontal view.

[0049] The properties of the proposed support basket were compared with those of a conventional wire mesh in a heat pump. This resulted in an improvement in the device's acoustics with identical power consumption. A further technical challenge is to be able to manufacture the plastic support basket using a simple, slide-free injection molding tool. The injection molding tool must be able to be opened in the axial direction in order to keep tool costs low. This can be achieved by inclining the support structure and the surrounding struts. In simple terms, this gives the basket structure the shape of a truncated cone with openings, for example a truncated cone with a top surface with a recess for the motor mount. In particular, the circumferential side wall of the basket structure can (essentially) have the shape of a truncated cone with openings.The circumferential side wall with openings can be formed by parts of the support struts 2 and by those annular (radial) circumferential struts 3 arranged on the side wall of the basket structure. Additionally, some of the annular circumferential struts 3 and the motor mount 4 are arranged on the top surface of the truncated cone.

[0050] The truncated cone shape inherently features the inclined position of the surrounding side wall. This results in an inclination of the walls of the basket structure relative to the axis of the support basket, and thus also of the injection mold, which in turn enables axial demolding of the mold without the use of slides. In other words, the geometry of the support basket is designed so that the mold can be opened in the axial direction and no additional slides are required. This results in advantages in mold costs and cycle time / process costs.

[0051] This inclined position is shown in Figs. 8a and 8b. Figs. 8a and 8b illustrate a demolding concept for the support basket. Fig. 8a shows the axis 12 of the support basket 1 (i.e., the truncated cone shape of the support basket 1) as well as the straight lines 13 formed by the support struts along two sections of the side wall inside the truncated cone shape. For example, sections of the side wall inside can have an angle of 0.5° (or at least 1°, or at least 2°, or at least 3°, or at least 4°, or at least 5°, or at least 6°) with the axis 12 of the truncated cone.More precisely, when divided into several sections (wherein the sections can each be delimited by a radially extending support strut 3), the sections of the side wall can each have an angle 9 of at least 0.5° (or at least 1°, or at least 2°, or at least 3°, or at least 4°, or at least 5°, or at least 6°) in the interior with respect to the axis 12 of the truncated cone. In Fig. 8a, for example, angles of 6.6° and 6.5° are shown. The respective angle 13 in the interior of the circumferential side wall of the truncated cone shape is formed by a geometry of the support struts 2 of the basket structure, wherein the annular circumferential struts 3 follow the geometry of the support struts 2 or remain within the profile of the support struts.

[0052] The division into two sections is highlighted again in Fig. 8b. The separation contour of the mold halves can be implemented accordingly by designing the plastic support basket (into two sections). One of the sections can be formed in the first mold half and the other section in the other mold half. Arrows show how the mold is demolded axially without the need for slides. Figs. 8a and 8b also show the contour of one half of the mold 11 (11a, 11b).

[0053] Accordingly, a method for producing the inventive support basket for a fan is also provided, in which the support basket is injection-molded from plastic using an injection molding tool. In this method, the injection molding tool is opened in a single direction and without the use of a slide.

[0054] The carrying basket is preferably manufactured using an injection molding process, preferably as a single piece. Various plastics can be used, each offering high stability and durability, particularly in outdoor areas. For example, the plastic from which the carrying basket is made can be polyamide (PA), polypropylene (PP), polybutylene terephthalate (PBT), polyetheretherketone (PEEK), acrylonitrile butadiene styrene (ABS), or polyphenylene sulfide (PPS).

[0055] Taking into account manufacturability and aerodynamic requirements, the support basket according to the invention, particularly through the design of the basket structure, offers easy demoldability while simultaneously improving acoustics. In addition to accommodating the fan on the motor mount, the support basket can also perform other functions. For example, the support basket(s) can comprise a cable guide or fastening that is an integral part of the support basket. In other words, the support basket can have an integrated cable guide or cable fastening. The cable(s) (for the fan) can be fastened, for example, using a clamp, clip, or cable duct. The cable duct can also be fully or partially closed with a cover.

[0056] In addition, contact protection can be made possible with the help of the support basket. In one variant, contact protection can be integrated into the support basket by providing the distance between the annular struts 3 (and optionally the support struts 2) according to the contact protection specifications or by providing additional struts and / or honeycombs in the injection-molded component. One such variant is shown in Figs. 9a to 9d. Figs. 9a to 9d show a support basket 1a with integrated contact protection. Fig. 9a shows the support basket 1a in an isometric view, Figs. 9b and 9c from the front and from the rear, respectively, and Fig. 9d shows the circumferential struts 3 again in detail. In this case, the support basket 1a is designed as contact protection. The support basket 1a of Figs. 9a to 9d differs from the support basket 1 of the previous figures in particular or exclusively in the number and spacing of the circumferential struts.

[0057] Alternatively, the support basket can be designed with additional contact protection, which can be removable or permanently attached. This variant is shown in Figs. 10a to 10d. In particular, circumferential struts 14 of a wire mesh are shown there, which form the separate contact protection. Fig. 10a shows an isometric view of the support basket with separate contact protection, Figs. 10b and 10c show the support basket with separate contact protection from the front and rear, respectively, and Fig. 10d shows the support basket and the wire mesh 14 in profile. The separate contact protection is arranged on the outside of the support basket. In principle, however, the separate contact protection can be attached to both sides, i.e. on the side facing the fan (inner width) or the side facing away from the fan (outside).Such a carrying cage, which is intended to accommodate a separate contact guard, can have a receiving structure for a separate contact guard, via which the separate contact guard can be releasably or permanently attached to the carrying cage. The contact guard can thus be attached to the carrying cage as an additional component either releasably (e.g., screwed or clipped) or permanently (e.g., glued, riveted, or welded). In this case, the method can further comprise attaching the separate contact guard to the carrying cage (releasably or permanently) on the receiving structure for the separate contact guard.

[0058] The same applies to a flow straightener function of the support basket. Again, in a first variant, the flow straightener can be integrated into the support basket, for example by additional struts, blades, or honeycombs included in the injection-molded component. In this case, the support basket is designed as a flow straightener. Alternatively, the support basket can be designed with an additional flow straightener. In this case, the support basket can have a receiving structure for a separate flow straightener, via which the separate flow straightener can be detachably or permanently attached to the support basket. The straightener can then be attached to the support basket as an additional component detachably (for example, screwed or clipped) or permanently (for example, glued or welded). In this case, the method can also further comprise attaching (detachably or permanently) the separate flow straightener to the support basket on a receiving structure for the separate flow straightener.

[0059] With regard to further advantageous embodiments of the device according to the invention, reference is made to the general part of the description and to the appended claims in order to avoid repetition.

[0060] Finally, it should be expressly pointed out that the above-described embodiments of the device according to the invention serve only to explain the claimed teaching, but do not limit it to the embodiments.

[0061] 1 carrying basket

[0062] 2 supporting struts

[0063] 3 Ring-shaped struts

[0064] 4 Engine mounting

[0065] 5 Mounting structure

[0066] 6 Skeletal line

[0067] 7 Fan

[0068] 8 Engine

[0069] 9 Impeller 0 Housing of a heat pump 1 Forming tool 2 Axis of a truncated cone of the

[0070] Carrying basket 3 Angle inside the side wall 4 Struts of the protective grille

Claims

Claims 1. A support basket for a fan, in particular for use in a heat pump, wherein the support basket comprises a basket structure with a motor mounting and is made of plastic.

2. A support basket according to claim 1, characterized in that the basket structure comprises a plurality of radially extending support struts and a plurality of annular struts, wherein the annular struts cross the support struts.

3. Carrying basket according to claim 2, characterized in that at least one of the annularly circumferential struts has an oval shape, so that a thickness of the at least one annularly circumferential strut increases in the inflow direction up to a maximum and decreases again in the outflow direction.

4. A support basket according to claim 2 or 3, characterized in that a first average thickness of the support struts in the air flow direction is at least as large as a second average thickness of the support struts orthogonal to the air flow direction.

5. Carrying basket according to one of claims 1 to 4, characterized in that the carrying basket is manufactured by injection molding and / or is made in one piece.

6. Carrying basket according to one of claims 1 to 5, characterized in that the circumferential side wall of the basket structure has substantially the shape of a truncated cone with openings.

7. Carrying basket according to claim 6, characterized in that sections of the side wall in the interior have an angle of at least 3° with respect to an axis of the truncated cone.

8. Carrying basket according to one of claims 1 to 7, characterized in that the carrying basket has an integrated cable guide or cable fastening.

9. Carrying basket according to one of claims 1 to 8, wherein the carrying basket is designed as a contact guard or has a receiving structure for a separate contact guard, via which the separate contact guard can be detachably or permanently attached to the carrying basket.

10. A carrying basket according to any one of claims 1 to 9, wherein the carrying basket is designed as a flow straightener or has a receiving structure for a separate flow straightener, via which the separate flow straightener can be releasably or permanently attached to the carrying basket.

11. Fan, in particular axial fan, with a support basket according to one of claims 1 to 10.

12. Fan according to claim 11, characterized in that the fan has an external rotor motor.

13. Heat pump with a fan, in particular an axial fan, and a support basket according to one of claims 1 to 11, wherein the fan is attached to a motor attachment of the support basket.

14. A method for producing a support basket for a fan, in particular for use in or with a heat pump, in particular for producing a support basket according to one of claims 1 to 10, the method comprising: Providing an injection molding tool for manufacturing the carrying basket; and Injection molding, by means of the injection molding tool, of the support basket, wherein the support basket comprises a basket structure with a motor mount and is made of plastic, and whereby the injection moulding tool can be opened in a single direction and without the use of a slide.

15. The method of claim 14, wherein the support basket has a receiving structure for a separate touch guard or a separate flow straightener, the method further comprising providing the separate touch guard or flow straightener, and attaching, to the receiving structure, the separate touch guard or flow straightener to the support basket.

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