Fan wheel and assembly with a fan wheel

Abstract

Fan wheel (20) as an assembly element for an assembly (1) with rotatably movable assembly elements comprising a centrally arranged fan wheel hub (21) and a plurality of fan wheel blades (22), wherein the fan wheel (20) has an influence on the mass distribution, characterized in that the influence on the mass distribution is formed by a partial adaptation of the geometry in at least one balancing area (24) of the fan wheel (20).

Description

[0001] The present utility model relates to a fan wheel as an assembly element for an assembly with rotationally movable assembly elements comprising a centrally arranged fan wheel hub and a plurality of fan wheel blades, wherein the fan wheel influences the mass distribution. Furthermore, the utility model relates to an assembly with such a fan wheel.

[0002] Electrical machines have long been state-of-the-art in their wide range of applications and diverse designs. In addition to the categorization into stationary, i.e., static electrical machines, and rotating, dynamic machines, a multitude of different designs are known within the dynamic category, for example, grouped according to the type of current used, such as direct current, alternating current, and three-phase alternating current, and various winding arrangements for generating a rotating magnetic field. Different operating modes of the machines can be realized using commutator machines, asynchronous machines, and synchronous machines.

[0003] Dynamic, electric motor drive units for generating rotary motions form a very large group. Applications are abundant in the state of the art, for example, in the drive trains of battery-electric vehicles, drives for elevators, compressors, heat pumps, cranes, air conditioning systems, etc. Electric motor drives are also used as auxiliary units in vehicles based on combustion technology, for example, as an assembly together with a fan impeller for cooling the engine or cooling fluid. For this purpose, a cooling air flow is supplied to a heat exchanger by the rotary-driven fan impeller.

[0004] In connection with rotational-dynamic components, it is known in the prior art that imbalances can occur. An imbalance can be static ("center of gravity error") or dynamic (moment imbalance, combination of static imbalances) in nature and depends primarily on the geometry and mass distribution. To reduce or eliminate imbalances, rotating components are balanced. This is achieved by influencing the mass distribution with the goal of ensuring that the rotational axis of the rotating component passes through the center of mass and / or that the rotation and principal axes of inertia are largely congruent. The mass distribution is usually influenced by adding balancing weights or partially removing component mass.

[0005] An example of balancing a rotating individual component is shown in DE 10 2013 212 341 A1. This proposes balancing a fan wheel by removing material, with the mass for the material removal being provided by additional knob-like elements. The knob-like additional elements are designed as an integral part of the fan wheel during its manufacture and merely increase the mass without supporting the actual fan wheel function. Balancing is achieved by partially and specifically reducing the mass of the knob-like elements, for example, mechanically by milling or drilling.

[0006] Another well-known method for mass-influencing balancing of individual components is the use of balancing weights. Mass imbalances are reduced or completely compensated by adding additional weights. The balancing weights are attached to the component to be balanced in a removable or permanent manner, for example, by clamping, gluing, or welding.

[0007] Balancing individual components is often a special case because in many applications, not only a single component rotates, but also components of the drive for the rotary movement, for example, a shaft or rotor of an electrical machine. This creates a rotating assembly consisting of at least two individual rotating components with a total unbalance composed of the individual unbalances of the individual components. Balancing a component only makes sense if it is certain that the other component is free of unbalance or has already been balanced separately. Rotating assemblies are preferably balanced with their total unbalance.

[0008] A clear example of total imbalance is the assembly consisting of a car rim, a valve, and a car tire. Together, they form a car wheel and each exhibits or causes an imbalance. Balancing a car wheel is performed as a complete assembly of rim, valve, and tire by balancing the mass distribution using additional weights.

[0009] EP 3 835 594 A2 discloses an assembly consisting of interconnected, rotating components which, as a whole, exhibit an imbalance and are balanced by material removal. The assembly essentially consists of an electric motor drive and a fan assembly. An electric motor assembly includes an electric motor and a fan assembly coupled to the electric motor and configured to rotate therewith about an axis. The fan assembly includes a hub with a core ring, a first inner ring surrounding the core ring, and a first plurality of circumferentially arranged ribs extending between the core ring and the first inner ring.The hub further includes a second inner ring surrounding the first inner ring, a second plurality of circumferentially arranged ribs extending between the first inner ring and the second inner ring, and a plurality of circumferentially arranged blades connected to an outer periphery of the hub.

[0010] The method for balancing the assembly comprises the steps of manufacturing the assembly by assembling the individual parts, i.e., coupling a fan assembly to an electric motor such that the fan assembly is configured to rotate about an axis. The fan assembly includes a hub having a first inner ring, a second inner ring surrounding the first inner ring, and a second plurality of circumferentially arranged ribs extending between the first inner ring and the second inner ring. Balancing is performed by removing a portion of at least one of the second plurality of ribs. A disadvantage is that ribs must first be provided in order to then partially reduce their mass. Essentially, this is the opposite of the balancing method in which balancing weights are added to the structure.The effort required for this is considerable, as first a component mass is produced that is functionally increased only for the balancing purpose and then the balancing is carried out by targeted material removal.

[0011] DE 10 2018 213 810 A1 discloses a balancing method for an assembly in which balancing weights are attached to a fan impeller by ultrasonic welding, depending on the optimal position for balancing. This means that the assembly is balanced by adding balancing weights to an assembly component, in this case the fan impeller. A disadvantage is that a complex ultrasonic welding process must be used, and only plastic balancing weights can be ultrasonically welded to a plastic fan impeller. Since the specific density of plastic is considerably lower than that of metal, for example, plastic balancing weights must have larger external dimensions. Another disadvantage is the noise generated by externally attached balancing weights due to air turbulence, particularly at higher speeds.

[0012] The object of the present utility model is to provide a method and a device which enables the production of balanced assemblies and at least partially reduces the disadvantages of known solutions.

[0013] The present utility model proposes to produce a balanced assembly state in assemblies with a first assembly element and at least one second assembly element by a specifically influenced mass distribution of the at least one second assembly element matched to the unbalance behavior of the first assembly element.

[0014] The present utility model recognizes that the targeted influencing of the mass distribution of at least one second assembly element by at least partially adjusting the geometry and / or wall thickness is particularly advantageous for providing a balanced assembly. This means that neither additional balancing weights nor the removal of additional balancing mass are used to influence the mass; rather, at least one second assembly element is adapted in its inherent individual element mass to the imbalance of the first assembly element. A balanced assembly within the meaning of the present utility model is an assembly in which at least two components move in a rotational manner and are largely balanced as a rotating unit.

[0015] It is particularly advantageous if the utility model concept is applied to an assembly consisting of an electric motor drive and a fan impeller. Such assemblies are found, among other things, in vehicles with cooling or air conditioning systems. However, the basic utility model concept is not limited to such assemblies.

[0016] Due to its complex geometry and the frequently used manufacturing method of plastic injection molding, the fan impeller's mass distribution can be influenced in a particularly diverse way. As the second component, it can compensate for any imbalance in the electric motor drive as the first component, thus achieving a balanced assembly. Fan impellers often have an outer ring that radially surrounds the fan impeller blades at the ends. This outer ring is particularly advantageous for influencing the mass distribution of the fan impeller due to its maximum distance from the rotational axis. Other suitable areas for influencing the mass distribution of the fan impeller include the fan impeller hub or the fan impeller blades.

[0017] It is intended that in order to influence the mass distribution of the second assembly element produced by plastic injection molding, the injection molding tool has adjustment options at suitable circumferential positions of the fan wheel in order to change wall thicknesses, component geometries or recesses already during the manufacturing process and to achieve the targeted influence of the mass distribution of the second assembly element coordinated with the previously determined imbalance of the first assembly element and to provide a balanced assembly after the assembly of the assembly elements.

[0018] The present utility model recognizes that influencing the mass distribution of the second assembly element by changing the wall thickness, component geometries, or recesses involves structural limitations. The component's strength, and in particular its structural integrity, must be guaranteed under all operating conditions after influencing the mass distribution. Structural component failure under the respective dynamic and static loads of the application is the dimensioning limit, at least for a lifetime design. Therefore, partial influencing of the mass distribution is subject to limits, for example, regarding the minimum residual wall thickness.

[0019] In the process for manufacturing a balanced assembly, the limit to load-dependent structural component failure and / or the service life specification to be achieved is maintained as a boundary value problem by at least partially maintaining minimum material wall thicknesses. Additional, case-specific parameters such as the static and dynamic loads on the assembly and the second assembly element, the material properties at least in the preferred range to be influenced for mass distribution, the structural strength of the second assembly element, as well as vibration behavior and the mass distribution-dependent resonance range over the intended speed range are taken into account when determining the minimum material wall thicknesses.

[0020] If the state of the balanced assembly cannot be achieved by influencing the mass distribution of the at least one second assembly element in a preferred region, for example due to a pronounced imbalance of the first assembly element, an analytical investigation is carried out to determine whether a first alternative region of the at least one second assembly element is suitable for achieving the balanced state of the assembly by influencing the mass distribution. For this purpose, the procedure is analogous to the procedure in the preferred region and it is checked whether the at least one alternative region has a wall thickness that is above the minimum material wall thickness after the required influencing of the mass distribution. It is also possible to influence the mass distribution in the preferred region and / or the first alternative region combined with one or more further alternative regions.

[0021] If the mass distribution is influenced by a geometric change, an analysis is carried out to determine whether the required geometric change results in a component strength that exceeds the required minimum component strength. The mass distribution can be influenced in this way and within the preferred range. If this condition is not met, the procedure described for influencing wall thickness is followed, and an analysis of one or more alternative ranges is included.

[0022] If the examination and analysis steps of the method for producing a balanced assembly result in the balanced state of the assembly with the unbalance behavior of the present first assembly element cannot be achieved by influencing the mass distribution of the at least one second assembly element in the preferred range and / or by including further alternative ranges, the following steps can follow depending on the unbalance severity: - the first assembly element is removed from the manufacturing process and marked as scrap or - the first assembly element is at least partially balanced separately and thus the mass distribution to be introduced into the assembly by the second assembly element for the provision of a balanced assembly is at least reduced and, or - influencing the mass distribution of the second assembly element is combined with conventional balancing procedures, for example, attaching balancing weights and, or - Compensation of at least part of the imbalance of the assembly by eccentrically and thus off-centerly combining the first and at least one second assembly element and, or - Influencing the mass distribution in the preferred and / or alternative areas by one or more insert weights which are accommodated inside the second assembly element.

[0023] These aforementioned steps can help reduce the number of assemblies with insufficient balancing quality and thus reduce the number of rejected assemblies and / or initial assembly elements.

[0024] The present utility model is explained in more detail below using an exemplary embodiment in conjunction with the figures. These show: Fig. 1 a sectional side view of an assembly with a first and a second assembly element and Fig. 2 a front view of the assembly with electric motor drive and fan wheel and Fig. 3 a perspective view of the assembly with a plurality of devices for influencing mass distribution and Fig. 4 the outer area of ​​the fan wheel in a sectional side view with outer ring and tool insert and Fig. 5 the outer area of ​​the fan wheel in a sectional side view with outer ring and device for influencing the mass distribution as well as Fig. 6 the front view of a section of the fan wheel with outer ring and a balancing area.

[0025] Fig. 1 shows a sectional side view of an assembly 1 with a first assembly element formed by an electric motor drive 10 and a second assembly element formed by a fan wheel 20. The electric motor drive 10, or its rotor 11, and the fan wheel 20 are joined together and form a common axis of rotation around which the assembly 1 can rotate. The assembly elements 11, 20 can be releasably joined together, for example by screwing. Preferably, the assembly elements 11, 20 are permanently joined together, for example by caulking or by a material bond of a plastic material to the fan wheel 20 or by gluing.

[0026] The Fig. The assembly elements shown in Figure 1, namely the electric motor drive 10 and the fan wheel 20 of the assembly 1, are exemplary in nature and explain the utility model concept applicable to rotating assemblies using this selected example.

[0027] Fig. 2 illustrates a front view of the assembly 1 with rotor 11 of the electric motor drive 10 and fan wheel 20. The rotor 11 is assembled with the fan wheel 20 in a rotational axis-centered manner within the fan wheel hub 21.

[0028] One possible embodiment of the combination of rotor 11 and fan wheel 20 is the one-piece formation of the overmolding of the rotor 11 and the fan wheel 20 using a plastic material, for example a polyamide plastic PA6 GF30. If this variant of the combination of rotor 11 and fan wheel 20 is selected, it is advantageous to realize this using an injection molding process. For this purpose, the rotor 11 is placed in an injection molding tool which has a suitable cavity for both the geometric shape of the overmolding of the rotor 11 and the geometric shape of the fan wheel 20. With the actual injection molding process, i.e. the injection of the plastic melt into the injection mold, both the overmolding of the rotor 11 and the fan wheel 20 as a second assembly element as well as the combination of both assembly elements 11, 20 are produced in a single process step.The rotor 11 is inserted into the injection molding tool in a defined position according to its previously determined imbalance, which is coordinated with the orientation and position of the influence on the mass distribution of the fan wheel 20.

[0029] In addition to the centrally arranged fan hub 21, the fan wheel 20 has a plurality of fan blades 22 and an outer ring 23 that surrounds the fan blades 22 at their radially outer ends. Because the outer ring 23 is arranged at the radially outer end of the fan wheel 20 and thus has a maximum distance from the center of rotation in its direction of rotation, the present utility model provides that the outer ring 23 has at least one balancing area 24 as a preferred area for influencing the mass distribution.

[0030] The at least one balancing region 24 is formed as a section of the outer ring 24, which, depending on the mass distribution influence, can have a wall thickness WW that partially differs from the wall thickness WA of the outer ring 23. The wall thickness WW of the balancing region 24 can be smaller, larger, or equal to the wall thickness WA of the outer ring 23.

[0031] In the circumferential direction of the outer ring 23, the at least one balancing region 24 extends in at least one partial circumferential section. Preferably, two or more balancing regions 24 are arranged in a symmetrical or asymmetrical distribution, wherein the balancing regions 24 can have identical or unequal wall thicknesses WW compared to one another. At least one balancing region 24 is a preferred region, and at least one further balancing region 24 is an alternative region and / or an additive region. Fig. The embodiment shown in Figure 2 has, by way of example, eight balancing areas 24 distributed uniformly over the circumference.

[0032] Fig. 3 includes a perspective view of assembly 1 with a plurality of mass distribution influencing devices 30. The arrangement illustrates the relative position of assembly 1 and the plurality of mass distribution influencing devices 30 within an injection molding tool (not shown). By way of example, eight mass distribution influencing devices 30 are arranged symmetrically and uniformly around the circumference of fan wheel 20 in order to influence the mass distribution of eight balancing regions 24 at eight positions on outer ring 23.

[0033] The device for influencing mass distribution 30 has at least one linear drive 31 and a tool insert 40. The tool insert 40 can be displaced via the linear drive 31, so that the cavity of the injection molding tool can be adjusted in the section of the balancing area 24 and its wall thickness WW can be adjusted in a way that influences mass distribution. A measuring device 44 can be provided for precisely measuring the position of the tool insert.

[0034] Fig. 4 comprises the outer area of ​​the fan wheel 20 in a sectional side view with outer ring 23 and tool insert 40. The rotation axis of the fan wheel 20 and the assembly 1 is in Fig. 4 parallel to the vertical.

[0035] The outer ring 23 of this exemplary embodiment has a first region that is axially parallel to the rotational axis of the fan wheel 20 and has an outer ring wall thickness WA. A second region of the outer ring 23 extends radially to the rotational axis of the fan wheel 20, forms the balancing region 24, and has a balancing region wall thickness WW. The two wall thickness regions WA, WW, with their extension directions largely at right angles to one another, merge seamlessly into one another through a radius region of the outer ring 24 that integrally connects both regions.

[0036] To influence the mass distribution, the balancing area wall thickness WW in the balancing area 24 is increased, decreased, or remains the same relative to the outer ring wall thickness WA, depending on the required balancing weight for balancing the assembly 1. The balancing area wall thickness WW, as a quasi-control variable for influencing the mass distribution of the fan wheel 20, is adjusted in this embodiment by a tool insert 40 with its end-side cavity region 43, which can be moved linearly and parallel to the rotational axis of the fan wheel 20.

[0037] The mass distribution is adjusted during the manufacturing process of the fan wheel 20 so that the fan wheel 20 thus manufactured exactly fits the electric motor drive 10 or its rotor 11 with its specific imbalance and forms the assembly 1.

[0038] As an alternative to the injection molding concept, in which the fan wheel 20 and the overmolding of the rotor 11 are manufactured in one injection mold, it may be provided to manufacture the fan wheel 20 through a separate injection molding step. In this case, when assembling the two assembly elements, both the correct assignment and their orientation and position relative to each other must be ensured. Suitable procedures for detachable or permanent assembly include, for example, screwing, hot-staking, gluing, and welding.

[0039] Fig. 5 shows the outer area of ​​the fan wheel 20 in a sectional side view with outer ring 23 and device for influencing mass distribution 30.

[0040] The device for influencing mass distribution 30 is essentially formed by a linear drive 31 with a linear plunger 32, which interacts with a tool insert 40. The linear plunger 32 is preferably designed with a rectangular or square cross-section and can be guided precisely and without play in an injection molding tool (also not shown) by support strips (not shown). For particularly precise guidance of the linear plunger 32, straight plunger sections 34 can be provided adjacent to the plunger bevel 33 in order to guide the linear plunger 32 in two areas and thus increase the guidance accuracy and the ability of the tool insert 40 to absorb transverse forces. The linear plunger 32 is guided with a linear degree of freedom in the linear plunger movement direction SB.

[0041] The tool insert 40 has a guide bore 41 with a bore bevel 42, which is designed to be compatible with the linear plunger 32 with a plunger bevel 33, so that the linear plunger 32 can be inserted into the guide bore 41 of the tool insert 40. The tool insert 40 is guided in its tool insert movement direction WB with a linear degree of freedom, thus supporting a linear movement.

[0042] As a result of the guided movement directions SB, WB and the interaction of the tappet bevel 33 of the linear tappet 32 ​​as well as the guide bore 41 with the bore bevel 42, the linear tappet movement direction SB of the linear tappet 32 ​​is translated into a tool insert movement direction WB of the tool insert 40. In a particularly advantageous manner, the design of the corresponding angle between the tappet bevel 33 and the bore bevel 42 allows for very precise adjustment of the position of the tool insert 40 along the path of the tool insert movement direction WB. In addition, depending on the angle formed, self-locking can be achieved between the tool insert 40 and the linear tappet 32, so that the forces acting on the tool insert 40 in the tool insert movement direction WB during the injection molding process are absorbed by the linear guide of the linear tappet 32.The suitable angle range of the angle between the linear center axis of the linear plunger 32 and the plunger bevel 33 is 2 degrees to 6 degrees, preferably 3 degrees to 5 degrees.

[0043] The distance traveled by the tool insert 40 along its tool insert movement direction WB can be determined indirectly and mathematically by measuring the distance of the linear ram 32 along its linear ram movement direction SB and the resulting transmission ratio by the angle of the ram bevel 33 and the bore bevel 42. Optionally, a measuring device 44 determines the linear distance of the tool insert 40 along its tool insert movement direction WB in order to precisely record the actual distance values.

[0044] Fig.6 shows the front view of a region of the fan wheel 20 with outer ring 23 and a balancing region 24. It is possible to provide exactly one balancing region 24 on the circumference of the outer ring 23; preferably, two or more balancing regions 24 are arranged in a symmetrical or asymmetrical distribution, wherein the balancing regions 24 can have identical or unequal wall thicknesses WW and / or length dimensions in the circumferential direction. Due to these identical and / or unequal geometric dimensions of the balancing regions 24, it is possible for the mass distributions to be very flexible and to be influenced over large ranges, and thus even significant imbalances of the first assembly element, which in this exemplary embodiment is formed by an electric motor drive 10 with a rotor 11, can be compensated for in order to achieve a largely balanced assembly 1.

[0045] The length dimension of at least one balancing area 24 in the circumferential direction can be specified within a range. The lower length dimension limit is determined by the still reasonably achievable influence on the mass distribution. Criteria for the upper length dimension limit are the size of the tool insert 40, the ratio of the length dimension of the circumference to the diameter of the outer ring 23, and the compressive forces of the plastic to be absorbed by the tool insert 40 during the injection molding process. Based on this, a length dimension of the balancing area 24 in the circumferential direction is 0.04 to 0.05 of the circumference of the outer ring 23 if eight balancing areas 24 are provided distributed around the circumference of the outer ring 23. Reference symbol 1 assembly 10 electric motor drive 11 Rotor 20 Fan wheel 21 Fan wheel hub 22 Fan blade 23 Outer ring 24 Balancing area 30 Device for influencing mass distribution 31 Linear actuator 32 linear tappets 33 Tappet bevel 34 straight tappet sections 40 tool insert 41 Guide hole 42 bore angle 43 Cavity area 44 Measuring device SB linear plunger movement direction WB tool insert movement direction WW wall thickness in the balancing area WA wall thickness outer ring QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2013 212 341 A1

[0005] EP 3 835 594 A2

[0009] DE 10 2018 213 810 A1

[0011]

Claims

[1] Fan wheel (20) as an assembly element for an assembly (1) with rotationally movable assembly elements comprising a centrally arranged fan wheel hub (21) and a plurality of fan wheel blades (22), wherein the fan wheel (20) has an influence on the mass distribution, characterized by that the mass distribution is influenced by a partial adaptation of the geometry in at least one balancing area (24) of the fan wheel (20). [2] Fan wheel (20) as an assembly element for an assembly (1) according to claim 1, characterized by that the partial adaptation of the geometry in at least one balancing area (24) of the fan wheel (20) takes place in a preferred area and, or at least one alternative area and, or an additive area. [3] Fan wheel (20) as an assembly element for an assembly (1) according to claim 1, characterized bythat the partial adaptation of the geometry is an adapted balancing area wall thickness WW of the balancing area (24). [4] Fan wheel (20) as an assembly element for an assembly (1) according to claim 3, characterized by that the minimum balancing area wall thickness WW of the balancing area (24) is limited by the component strength of the fan wheel (20). [5] Fan wheel (20) as an assembly element for an assembly (1) according to claim 1, characterized by that the fan wheel (20) has an outer ring (23) with at least one balancing area (24). [6] Fan wheel (20) as an assembly element for an assembly (1) according to claim 5, characterized by that the outer ring (23) has a region axially parallel to the axis of rotation of the fan wheel (20) and a radial region, wherein the at least one balancing region (24) is arranged in the region of the outer ring (23) extending radially to the axis of rotation. [7] Fan wheel (20) as an assembly element for an assembly (1) according to claim 5, characterized by that the at least one balancing region (24) comprises a plurality of balancing regions (24) distributed symmetrically or asymmetrically on the circumference of the outer ring (23). [8] Fan wheel (20) as an assembly element for an assembly (1) according to claim 5, characterized by that the at least one balancing area (24) has a balancing area wall thickness WW which deviates from the outer ring wall thickness WA of the outer ring (23) and thus influences the mass distribution of the fan wheel (20). [9] Fan wheel (20) as an assembly element for an assembly (1) according to claim 5, characterized by that the at least one balancing region (24) has an extension in the circumferential direction which is 0.04 to 0.06 of the circumferential length of the outer ring (23). [10] Assembly (1) with rotationally movable assembly elements comprising a first assembly element formed by a rotor (11) and at least one second assembly element formed by a fan wheel (20), wherein the rotor (11) and the fan wheel (20) are jointly rotatably movable and jointly largely balanced by being combined, wherein the joint extensive balancing is achieved by influencing the mass distribution of the fan wheel (20). [11] Assembly (1) according to claim 10, characterized by that the assembly is formed in one piece from a polyamide plastic PA6 GF30.

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