Patent Application
20170306974
This application claims foreign priority under 35 U.S.C. ยง119(a)-(d) to Application No. EP 16166124.4 filed on Apr. 20, 2016, the entire contents of which are hereby incorporated by reference.
The disclosure relates to a profiled blade for a fan impeller, comprising a profiled body produced from at least one bent sheet metal strip. The disclosure further relates to a fan impeller provided with such a profiled blade.
According to prior art known to the applicant but not published in print, profiled blades for fan impellers are produced in a cost-effective way by bending an oblong sheet metal strip transversely to a longest edge. In this bending process, opposing first and second end region edges of the sheet metal strip are brought close to one another. For this bending process, it is possible, for example, to use a bending device with the aid of which a profile nose is created in the bending region. In the course of the bending process, a U-shaped profiling is temporarily created, which becomes a drop-shaped profiling by continuing the bending process. This drop-shaped profiling represents the final state of the bending process. In a subsequent machining step, an adhesive and/or positive joint between adjacent end region edges of the sheet metal strip can then be provided in order to produce a stable profiled blade. By way of example, it is provided that the adjacent end region edges of the sheet metal strip are wended and/or bonded and/or clinched (beaded) to one another.
The disclosure is based on the problem of providing a profiled blade and a fan impeller with such profiled blades with an improved rigidity for the profiled blades.
According to a first aspect of the disclosure, this problem is solved with a profiled blade comprising a profiled body produced from at least one sheet metal strip and comprises a profile top part with a convex curvature, a profile bottom part located at a distance from the profile top part and a first and a second profile nose, wherein each of the profile noses has a convex curvature and joins the profile top part to the profile bottom part at the ends, wherein the profile top part and/or the profile bottom part are/is divided into at least two profile sections, wherein a first profile section is joined to the first profile nose and wherein a second profile section is joined to the second profile nose, and wherein a first free end region of the first profile section is joined to a second free end region of the second profile section by adhesive force/adhesive bond.
In such a profiled blade, the at least one joint zone, which is, in a design of the profiled blade from one or more sheet metal strips, necessary for joining end regions of the sheet metal strip(s), can be relocated from the zones of the profiled blade which are highly loaded by the occurring forces to less highly loaded zones. As a result, it is possible to provide profiled blades which, in addition to an aerodynamically favorable profiling, ensure a reliable production process and a high fatigue strength, in particular with different profiling for a pressure side and a suction side of the profiled blade.
While the profile top part is always convex, the profile bottom part can be straight or convex or concave depending on application. In this, it has to be assumed that the profiling of the profiled body is always designed as a closed ring, preferably with a consistent curvature. As a result of the angling of the at least one end region and the placement of the angled section of this end region between the profile top part and the profile bottom part, an advantageous joint zone can be created for joining the profile sections by adhesive force. Possible methods for joining the profile sections by adhesive force/adhesive bond include welding, soldering or bonding methods in particular.
It is advantageous if a free end region of at least one profile section is angled relative to the profile top part and the profile bottom part and located between the profile top part and the profile bottom part. This increases a contact area between the two end regions of the profile sections, ensuring improved strength for joining the end regions by adhesive force.
It is expedient if a free end region of a profile section is in planar contact with a contact surface of another profile section which is strip-shaped and offset against a surface of the profiled body. If a soldering or bonding method is used, the contact surface forms at the angled section a soldering or bonding gap with a large contact surface between the two profile sections and thereby creates a mechanical joint with a high load-bearing capacity.
It is preferred if the contact surface is oriented parallel to the surface of the profiled body. In this way, a homogenous (welding or soldering or bonding) gap is formed between the two profiled sections, which, in particular if a welding or bonding method is used, is advantageous for a reliable mechanical coupling between the two profile sections. If a spot-welding method is used, the end region of the end region in contact with the contact surface and the section of the end region which defines the contact surface serve as a doubling of the sheet metal material. It is preferably provided that the contact surface is curved in the same way as the associated surface of the profiled body in order to ensure as constant as possible a gap width both in the longitudinal and in the transverse direction of the gap.
In an advantageous further development, it is provided that the angled free end region of the at least one profile section joins the profile top part to the profile bottom part. In this way, the angled free end region adopts, in addition to creating an advantageous contact surface for the respective other profile section, the function of a reinforcing strut which reinforces the profile top part against the profile bottom part, thereby stabilizing it against bending moments acting on the profiled blade in particular. The angled free end region of the at least one profile section is preferably designed such that it joins the profile top part to the profile bottom part in a region of maximum distance from the profile bottom part, whereby a particularly advantageous reinforcement effect can be obtained for the profiled blade. For joining the angled free end region of the profile section to the profile top part or the profile bottom part located at a distance, the same adhesive joining method is preferably used as for joining the two profile sections. By way of example, it is provided that both adhesive joints are created by welding, in particular spot-welding. Alternatively, another joining method can be used, which is possibly matched to the joining method for the two profile sections. Purely by way of example, if a welding method is used for the two profile sections, a thermally curing bonding method can be used for the adhesive joint between the angled free end region of the profile section and the opposite profile top part or profile bottom part. In this case, the adhesive used is activated by the heat introduced in the welding process.
In a further development, it is provided that the profile bottom part has a concave curvature and/or that the profile bottom part comprises at least two profile sections. If the profile bottom part is designed with a concave curvature, a corresponding profiled blade has an aerodynamically favorable profiling if used in a fan impeller. If the profile bottom part is in addition or alternatively designed with at least two profile sections and such profiled blades are used in a fan impeller, the joint zone between the two profile sections lies in a region of the profiled blade which is subjected to low mechanical loads. Compared to joint zones arranged differently, the forces acting on the joint zone are relatively low, so that a reliable joint can be obtained between the two profile sections.
It is advantageous if at least one of the free end regions is additionally joined by adhesive force to the profile bottom part, the profile top part or a profile element.
It is preferably provided that the profiled body is formed from precisely one sheet metal strip. This reduces the number of joint zones to a minimum, so that the production costs for the profiled blade can likewise be held at a low level. It further ensures an advantageous flow of forces within the profiled blade, which is not affected by a plurality of joint zones, so that a material-saving and therefore weight-saving design of the profiled blade can be obtained from this viewpoint as well.
It is expedient if both profile sections of the profile top part or the profile bottom part have a free end region which is angled relative to the profile top part and the profile bottom part and which extends between the profile top part and the profile bottom part. Both free end sections of the profile sections can therefore be used as reinforcing struts against the opposite profile top part or profile bottom part, whereby a profiled blade with a geometry capable of bearing particularly high loads can be obtained. By way of example, it can be provided that both end regions, starting at a parting line between the two profile sections where an adhesive joint of the two profile sections is created, in particular by welding, extend at an acute angle relative to one another towards the opposite profile top part or profile bottom part. Alternatively, it can be provided that a gap, in particular in the manner of a groove, which determines the course of the surfaces of the profile top part or profile bottom part even after the establishment of the adhesive joint, is formed between the two angled end regions.
It is preferably provided that each of the angled free end regions of the profile sections has a strip-shaped contact surface offset against a surface of the profiled body and that a profile element joins adjacent contact surfaces and determines the surface of the profiled body in some regions. The profile element therefore has the task of covering the in particular groove-shaped gap between the angled end regions of the profile sections, thereby ensuring a surface for the profile top part and/or the profile bottom part which is smooth to the greatest extent at least. By way of example, it is provided that an envelope around a profiled body has to the greatest extent a drop shape, in particular with a consistent curvature. The profile element is preferably designed as a sheet metal strip and is placed on the contact surface flush with the surfaces of the profile sections and joined to the profile sections by adhesive force.
According to a second aspect of the disclosure, a fan impeller comprises a disc-shaped circular blank which is designed coaxial with an axis of rotation and comprises a hub assembly as well as a ring arranged coaxially with the axis of rotation and at a distance from the circular blank and a plurality of profiled blades, each of them comprising a profiled body produced from at least one bent sheet metal strip and which comprises a profile top part with a convex curvature, a profile bottom part located at a distance from the profile top part and a first and a second profile nose, wherein each of the profile noses has a convex curvature and joins the profile top part to the profile bottom part at the ends, wherein the profile top part and/or the profile bottom part are/is divided into at least two profile sections, wherein a first profile section is joined to the first profile nose and wherein a second profile section is joined to the second profile nose, and wherein a first free end region of the first profile section is joined to a second free end region of the second profile section by adhesive force, which blades are arranged with pre-settable angular spacing in an annular spatial volume around the axis of rotation and fixed with opposite axial end faces to the circular blank and the ring.
A profiled blade designed according to the first aspect of the disclosure can be produced using a method comprising the following steps: the provision of a sheet metal strip to a forming device, the forming of the sheet metal strip to produce a profile top part with a convex curvature, a profile bottom part placed at a distance from the profile top part and a first and a second profile nose which join the profile top part and the profile bottom part at the ends, so that two profile sections each are formed at the profile top part and/or the profile bottom part, wherein a first profile section is joined to the first profile nose and a second profile section is joined to the second profile nose and wherein a free end region of at least one profile section is angled relative to the profile top part and the profile bottom part and located between the profile top part and the profile bottom part, and the fixing by adhesive force of at least one section of the end region on an adjacent section of the profile top part and/or the profile bottom part.
Advantageous variants of the disclosure are shown on the drawing, of which:
In the embodiments of profiled blades 1, 41, 81, 121, 161, 201, 241, 281, 321, 361, 401 described in greater detail below, structures of identical function are identified by the same reference numbers, increased by 40 in each case. The respective structures are described only once in each case. Initially, there will be an explanation of the profiled blade 1 shown in greater detail in
A profiled blade 1 shown in
In the illustrated embodiment, it is provided that the sheet metal strip 2 has been bent, at a distance from the respective end regions 5, 6 which corresponds to approximately 25 percent of the respective overall length of the two longest edges 3, 4, in opposite directions and a right angles to the two longest edges 3, 4, using different bending radii which are considerably larger than a material thickness of the sheet metal strip 2. This forming process results in a profiled body 7 having, purely by way of example, a constant profiling along a profile axis 8.
The profiled body 7 of the profiled blade 1 shown in
In the profiled blade 1, it is, purely by way of example, provided that the profile top part 9 is formed from two profile sections 17, 18, a first profile section 17 extending between the first end region edge 5 and the first profile nose 11, while a second profile section 18 extends between the second end region edge 6 and the second profile nose 12. In the illustrated embodiment, it is provided that a surface 19 of the profile top part 9 is defined by a top side 20 of the first profile section 17 and by a top side 21 of the second profile section 18, and that an end region 22 of the first profile section 17, which can also be described as a first end region 22, lies on the second profile section 18 in a manner described in greater detail below. The end region 23 of the second profile section 18, which can also be described as a second end region 23, extends from the top side 21 into an interior 14 of the profiled blade 1 which, with the exception of open end faces, is bounded by the sheet metal strip 2. Starting from the top side 21 of the second profile section 18, the end region is provided with two at least substantially rectangular and opposite folds 24, 25 in order to form a strip-shaped contact surface 26 offset against a surface 19 of the profiled body 7 and preferably extending parallel to the surface 20 of the first profile section 17 and offset by the material thickness of the sheet metal strip 2. From the contact surface 26, the end region 23 extends, after a further at least substantially rectangular fold 27, at right angles to a concave inner surface 28 of the profile bottom part 10 and is at the end bent once more at right angles with a fold 31. This forms a contact surface 29, which is parallel to the inner surface 28 and can be used for joining to the inner surface 28 by adhesive force.
By way of example, it is provided that the two profile sections 17, 18 are welded to one another at the surface 19 in a manner not shown in detail in the region of a parting line 30. Following the welding of the parting line 30, it can further be provided that the contact surface 29 is joined to the inner surface 28 by adhesive force using a liquid adhesive. Alternatively, the two profile sections 17, 18 can be soldered, exclusively welded or exclusively bonded to one another.
In the second embodiment of a profiled blade 41 shown in
In the third embodiment of a profiled blade 81 shown in
The profiled blade 121 shown in
By way of example, it can be provided that the profiled blades 1, 41, 81, 121, 161, 201, 241, 281, 321, 361, 401 described above are used in the production of a fan impeller 560 as shown, purely by way of example, in
As a result of the design of the profiled blades 1 as profiled bodies 7, a very strong and cost-effective fan impeller 560 is obtained in combination with the disc-shaped circular blank 563 and the ring 564.
The profiled blades 161, 201, 241, 281, 321, 361, 401 and 441 shown in
In the profiled blades 161, 201, 241 of the first group, it is provided that the profile top parts 169, 209, 249 and the profile bottom parts 170, 210, 250 of the respective profiled bodies 167, 207, 247 are divided into profile sections 177, 217, 257 and 178, 218, 258, and that end regions 182, 222, 262 and 183, 223, 263 are arranged opposite one another with their end faces and joined to one another by adhesive force. To ensure a dimensional stability for the profiled blades 161, 201, 241, a profile element 194, 234, 274 adhesively joined to facing inner surfaces of the end regions 182, 222, 262 and 183, 223, 263 is in each case located between the end regions 182, 222, 262 and 183, 223, 263. In the embodiment according to
The profiled blades 281, 321, 361, 401, 441 of the second group can be described as variants or further developments of the profiled blades 1, 41, 81, 121, wherein, as in the case of the profiled blades 161, 201, 241 of the first group, both the profile top parts 289, 329, 369, 409, 449 and the profile bottom parts 290, 330, 370, 410, 450 are divided into profile sections 297, 337, 377, 417, 457 and 298, 338, 378, 418, 458. As in the case of the profiled blades 1, 41, 81, 121, at least one of the end regions 302, 342, 382, 442, 462 and 303, 343, 383, 443, 463 of the profiled blades 281, 321, 361, 401, 441 is profiled in such a way that it can serve as a contact surface for an opposite end region each.
Accordingly, the profiled blade 281 according to
In the profiled blade 321, both end regions 343 of the profile top part 329 and the profile bottom part 330 are folded twice in opposite directions, thereby forming contact surfaces for the two end regions 342 of the profile top part 329 and the profile bottom part 330.
In the profiled blade 361, the end region 382 of the profile section 377 of the profile top part 369 rests against a contact surface of the folded end region 383 of the profile section 378. Furthermore, the end region 383 of the profile section 378 of the profile bottom part 370 rests against a contact surface of the folded end region 377 of the profile bottom part 370. Accordingly, the profiled blade 361 has two reinforcing struts between the profile top part 369 and the profile bottom part 370.
In the profiled blades 401 and 441, the end regions 423 of the profile top part 409 and the profile bottom part 410 form contact surfaces for the end regions 422 of the profile top part 409 and the profile bottom part 410. The end regions 423 are in addition folded in such a way that the end region 423 of the profile top part 409 is arranged with its end face opposite the end region 423 of the profile bottom part 410, whereby a gap not identified in detail is formed, which can be joined by adhesive force before the end regions 422 of the profile top part 409 and the profile bottom part 410 are joined to the contact surfaces by adhesive force.
The profiled blade 441 is a variant of the profiled blade 401, wherein the end region 463 of the profile top part 409 forms a contact surface both for the end regions 462 of the profile top part 449 and the profile bottom part 450 and for the end region 463 of the profile bottom part 450. In this case, it can likewise be provided that end regions 463 of the profile top part 449 and the profile bottom part 450 are first joined together by adhesive force and that the end regions 462 are then joined to the contact surfaces of the end regions 463 by adhesive force.
| Number | Date | Country | Kind |
|---|---|---|---|
| 16166124.4 | Apr 2016 | EP | regional |
