turbofan

Abstract

To enhance the positioning accuracy of pre-fusion two components while achieving a function for escaping burrs generated at ultrasonic fusion and a function for suppressing diffusion of oscillation energy.SOLUTION: In a turbofan 1, a first component 7 having a plane part 2 and a plurality of plate-shaped blade parts 4 erected from the plane part 2, and a second component 8 provided with a plurality of groove parts 31 in which end parts 41 of the blade parts 4 are accommodated, are fused to each other by ultrasonic fusion. Each of the groove parts 31 has a groove width wider than a plate thickness of the end part 41 of each of the blade parts 4. The turbofan 1 has one set of positioning ribs 20 for partially filling two clearances formed at both sides of the end part 41 in a plate thickness direction in a pre-fusion state. The one set of the positioning ribs 20 protrude from the end part 41 of at least one blade part 4 of the plurality of blade parts 4, and from a side face of at least one groove part 31 of the plurality of groove parts 31 respectively in the plate thickness direction, and abut on side face of the groove part 31 and the end part 41 of the blade part 4 respectively.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a turbofan formed by ultrasonically welding a first part and a second part having a plurality of blades. [Background technology]

[0002] Conventionally, turbofans have been known in which a plurality of blades arranged around a rotation center are sandwiched between two opposing flat plate components. For example, Patent Document 1 discloses a turbofan including a vaned shroud with a plurality of blades integrally molded therein and a main plate. In Patent Document 1, the turbofan including two flat plate components (the vaned shroud and the main plate) is formed by fitting the plurality of blades into a plurality of fitting portions recessed in the main plate and welding the fitting portions and the blades together by ultrasonic welding. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6899245 Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, when a turbofan is formed by ultrasonically welding two components together, as in Patent Document 1, it is required that the non-welded portions of the two components do not come into contact with each other before welding. In other words, it is required that a gap be formed between the two components to prevent contact between the non-welded portions. This allows burrs generated during welding to escape and prevents dispersion of the vibration energy of ultrasonic welding. On the other hand, the formation of the gap between the two components causes play between the two components. This makes it difficult to stabilize the positions of the two components before welding, making it difficult to attach the two components with precision.

[0005] The present invention has been devised in view of the above-mentioned problems, and one of its objectives is to improve the positioning accuracy of two parts before welding while realizing the function of removing burrs generated during ultrasonic welding and the function of suppressing dispersion of vibration energy. However, in addition to this objective, another objective of the present invention is to achieve the effects derived from the configurations shown in the below-mentioned embodiments for carrying out the invention, which cannot be obtained by conventional techniques. [Means for solving the problem]

[0006] The disclosed turbofan can be realized in the following disclosed aspects or applications, and solves at least some of the above problems. (1) A turbofan disclosed herein is a turbofan formed by ultrasonically welding together a first component having a flat surface extending in a direction perpendicular to a rotation center and a plurality of plate-like blades erected from the flat surface and extending outward from the rotation center around the rotation center, and a plate-like second component having a plurality of grooves recessed therein into which the extended ends of each of the blades fit. Each of the grooves has a width wider than the thickness of the blade at the end, and the turbofan has a pair of positioning ribs that partially fill two gaps that appear on both sides of the end in the thickness direction when the end is fitted in the groove, and each of the pair of positioning ribs protrudes in the thickness direction from the end of at least one of the plurality of blades and abuts against a side surface of the groove, or protrudes in the thickness direction from the side surface of at least one of the plurality of grooves and abuts against the end of each of the blades.

[0007] (2) In the case of (1) above, each of the blade portions preferably has a plurality of welding ribs that protrude from the end face of the end portion and are heated when the first component and the second component are welded. In this case, the plurality of welding ribs preferably extend intermittently along the extension direction of the end portion. Also, in this case, the positioning rib preferably is located at a gap between the plurality of welding ribs in the extension direction of the end portion, or is located at a gap between the plurality of welding ribs in the extension direction of the groove when the end portion is fitted in the groove.

[0008] (3) In the case of (1) or (2) above, it is preferable that the positioning rib provided in one of the two gaps and the positioning rib provided in the other gap have the same amount of protrusion in the plate thickness direction.

[0009] (4) In any one of the above cases (1) to (3), it is preferable that the positioning rib abuts linearly against the side surface of the groove portion in the depth direction of the groove portion, or against the end portion in the vertical direction of the blade portion. (5) In the case of (4) above, it is preferable that the positioning rib has an arc shape when viewed from the direction of the rotation center.

[0010] (6) In any one of the above (1) to (5), the end of the blade preferably has a curved shape when viewed from the direction of the rotation center. In this case, the set of positioning ribs is preferably provided in the groove. Also, in this case, the positioning rib provided in one of the two gaps and the positioning rib provided in the other are preferably arranged so that the normals to the positions where the positioning ribs abut against each other are aligned.

[0011] (7) In any one of the above (1) to (6), it is preferable that the positioning rib does not protrude from the gap toward the rotation center. (8) In any one of the above cases (1) to (7), it is preferable that the set of positioning ribs be provided on the ends of two or more of the plurality of blade portions that are positioned at equal intervals around the rotation center, or on the groove portions into which the ends fit. [Effects of the Invention]

[0012] The disclosed turbofan can improve the positioning accuracy of two parts before welding, while realizing the functions of removing burrs that occur during ultrasonic welding and suppressing the dispersion of vibration energy. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is an axial cross-sectional view of a fan motor to which a turbofan according to an embodiment is applied; [Figure 2] FIG. 2 is an exploded perspective view showing a state before the turbofan of FIG. 1 is formed. [Figure 3] FIG. 2 is a partial cross-sectional perspective view of the turbofan of FIG. 1. [Figure 4] FIG. 4 is an enlarged view of the X portion of FIG. [Figure 5] 5 is an enlarged view of a part (the part shown in FIG. 4) of a first part included in the turbofan of FIG. 1 before the first part is welded to a second part. [Figure 6] FIG. 3 is an enlarged view of a portion Y in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0014] A turbofan will be described as an embodiment with reference to the drawings. The embodiment described below is merely an example, and is not intended to exclude various modifications or applications of techniques not explicitly described in the embodiment. The configurations of the present embodiment can be modified in various ways without departing from the spirit of the invention. Furthermore, they can be selected or combined as needed.

[0015] [1. Configuration] Fig. 1 is an axial cross-sectional view of a fan motor 10 to which a turbofan 1 according to this embodiment is applied, and Fig. 2 is a perspective view showing the state before the turbofan 1 according to this embodiment is formed. As shown in Fig. 2, the turbofan 1 according to this embodiment includes two components 7 and 8, which are formed by welding the two components 7 and 8 together using ultrasonic welding. The turbofan 1 is a fan that draws in air from the side of the center of rotation C and sends it outward (in a direction away from the center of rotation C), and is also called a centrifugal fan.

[0016] Hereinafter, the direction in which the center of rotation C of the turbofan 1 extends will be referred to as the axial direction (direction of the center of rotation), the direction perpendicular to the center of rotation C and away from the center of rotation C will be referred to as the radial direction, and the direction perpendicular to the center of rotation C and circumferential around the center of rotation C will be referred to as the circumferential direction. As shown in Figure 1, the fan motor 10 is configured by incorporating the turbofan 1 and a motor unit 12 as a drive source for rotating the turbofan 1 in a housing 11 that forms the outer shell of the fan motor 10.

[0017] The motor unit 12 includes a shaft 13, a rotor 14 that rotates integrally with the turbofan 1 via the shaft 13, and a stator 15 disposed inside the rotor 14. In other words, the fan motor 10 is a so-called outer rotor brushless motor. The center of rotation of the shaft 13 coincides with the center of rotation C of the turbofan 1. The rotor 14 is provided with a cup-shaped rotor yoke 16 and a magnet 17 fixed to the inner peripheral surface of the rotor yoke 16. In this embodiment, the rotor yoke 16 has a generally truncated cone shape in which the outer diameter of one axial side (upper side in the figure) is smaller than the outer diameter of the other axial side (lower side in the figure). The shaft 13 is press-fitted and fixed radially inside the rotor yoke 16. This allows the rotor 14 to rotate integrally with the shaft 13 and the turbofan 1.

[0018] As described above, the turbofan 1 is a fan that draws air from the rotation center C side and sends it outward. It includes two plate-shaped flat portions 2, 3 arranged opposite each other in the axial direction and a plurality of blades 4 disposed between the two flat portions 2, 3. A hole 1h that forms an intake airflow path for the turbofan 1 is axially formed through one of the two flat portions 2, 3. Here, a turbofan 1 is illustrated in which the hole 1h for the intake airflow path is formed in the flat portion 3 arranged on one axial side (hereinafter referred to as the "second flat portion 3"). That is, the turbofan 1 of this embodiment draws air from one axial side and sends it outward in the radial direction, and the second flat portion 3 has an annular shape with the hole 1h formed on its radially inner side. Note that the second flat portion 3 illustrated here is inclined radially so that it is positioned toward the other axial side as it moves from the radially inner side to the radially outer side. However, the shape of the second flat portion 3 is not limited to this, and it does not have to be inclined radially.

[0019] The flat portion 2 (hereinafter referred to as the "first flat portion 2") disposed on the other axial side has an annular shape perpendicular to the center of rotation C. A boss portion 5 and a fitting portion 6 are provided on the radially inner portion of the first flat portion 2. The boss portion 5 supports the shaft 13 and covers the rotor yoke 16 from one axial side. The boss portion 5 has a substantially truncated conical shape corresponding to the outer shape of the rotor yoke 16. The end of the shaft 13 on one axial side is fixed (for example, press-fitted) to the radially inner portion of the boss portion 5. The fitting portion 6 is an annular portion protruding from the radially inner portion of the first flat portion 2 to the other axial side. The rotor yoke 16 is fitted into and bonded to the fitting portion 6. The turbofan 1 is fixed to the shaft 13 and the rotor 14 so as not to rotate relative to them by fixing the boss portion 5 to the end of the shaft 13 on one axial side and externally fitting and bonding the fitting portion 6 to the rotor yoke 16.

[0020] Of the two components 7, 8 that form the turbofan 1, the first component 7 has one of the two flat surfaces 2, 3 and a plurality of blades 4. The other component 8 has the other of the two flat surfaces 2, 3. As shown in FIG. 2 , the turbofan 1 of this embodiment includes a first component 7 that has a first flat surface 2 and a plurality of blades 4, and a second component 8 that has a second flat surface 3. The first component 7 also includes a boss 5 and a fitting portion 6. In the first component 7, the first flat surface 2, blades 4, boss 5, and fitting portion 6 are integrally molded. In other words, the first component 7 is a component in which the components 2 to 6 of the turbofan 1 described above are integrally molded except for the second flat surface 3, and the second component 8 can be said to be the second flat surface 3 itself.

[0021] As shown in FIGS. 3 and 4 , the turbofan 1 is formed by fitting end portions 41 on one axial side of the plurality of blade portions 4 of the first component 7 into groove portions 31 in the second flat portion 3 of the second component 8, and then ultrasonically welding the end portions 41 and the groove portions 31 together. More specifically, a welding rib 43 (see FIG. 5 ), which will be described later, of the end portions 41 and a bottom surface 32 (see FIG. 4 ), which will be described later, of the groove portions 31 are joined by ultrasonic welding. Hereinafter, the state before the first component 7 and the second component 8 are ultrasonically welded together will be referred to as the “pre-welding state,” and the state after the first component 7 and the second component 8 are welded together (the state shown in FIGS. 3 and 4 ), will be referred to as the “post-welding state.” The pre-welding state includes a state in which the end portions 41 of the blade portions 4 are fitted into the groove portions 31 before welding.

[0022] As shown in FIG. 3 , the plurality of blades 4 extend upright from a first surface 2F of the first flat surface 2 facing the second flat surface 3. Each blade 4 has a plate shape extending from the rotation center C toward the outside, i.e., radially outward, around the rotation center C. In this embodiment, the extending direction of the blades 4 coincides with the axial direction. The turbofan 1 of this embodiment rotates counterclockwise when viewed from one axial side, and the extending direction of the blades 4 is curved so that the radially outer portions of the blades 4 are shifted clockwise relative to the radially inner portions when viewed from one axial side. Note that when the turbofan 1 rotates clockwise when viewed from one axial side, the extending direction of the blades 4 may be curved so that the radially outer portions of the blades 4 are shifted counterclockwise relative to the radially inner portions when viewed from one axial side. Hereinafter, the direction perpendicular to both the extending direction (longitudinal direction) and the axial direction (standing direction) of the blade portion 4 will be referred to as the "plate thickness direction."

[0023] The multiple blades 4 all have the same shape and are arranged at equal intervals so as to circle the center of rotation C. While this embodiment illustrates 13 blades 4, the number of blades 4 is not limited to this. Furthermore, the blades 4 of this embodiment do not have a uniform thickness H1 (dimension in the thickness direction) in the extension direction, with the thickness H1 becoming thinner further outward from the center of rotation C, but the thickness H1 of the blades 4 may also be uniform in the extension direction.

[0024] As shown in Figure 4, the plate-shaped blade portion 4 has two surfaces 4L, 4R that face opposite each other in the circumferential direction. When the turbofan 1 rotates, one of the two surfaces 4L, 4R serves as a positive pressure surface that pushes out air, and the other serves as a negative pressure surface. Hereinafter, of the two surfaces 4L, 4R, the surface that faces clockwise in the circumferential direction when viewed from one axial side will be referred to as the first pressure surface 4L, and the surface that faces counterclockwise will be referred to as the second pressure surface 4R. In the following description, the terms "clockwise" and "counterclockwise" refer to the directions when viewed from one axial side.

[0025] Before welding, as shown in FIG. 5 , end 41 of each blade portion 4 has a plurality of welding ribs 43 protruding from end surface 42. As described above, welding ribs 43 are joined to bottom surface 32 of groove portion 31, and are heated and melted when first component 7 and second component 8 are welded together (hereinafter simply referred to as "during welding"). End surface 42 is the surface at the upright tip of blade portion 4 (a surface that extends in the thickness direction and extension direction, intersecting the upright direction of blade portion 4), and welding ribs 43 protrude from end surface 42 in the same direction as the upright direction of blade portion 4. The plurality of welding ribs 43 extend intermittently along the extension direction of end portion 41. Here, two welding ribs 43 are shown as an example, spaced apart from each other in the extension direction. The shape of each welding rib 43 is, for example, a triangular prism protruding from the end face 42 so that the apex is positioned on the center line C1 in the plate thickness direction of the end portion 41 (hereinafter referred to as the "plate thickness center line C1").

[0026] As shown in Fig. 2, second flat portion 3 is provided with a plurality of grooves 31 recessed from a second surface 3F of second flat portion 3 facing first flat portion 2 toward one side in the axial direction. Ends 41 of the plurality of blades 4 fit into each of the plurality of grooves 31 before welding. For this reason, the same number of grooves 31 as the number of blades 4 (13 in this embodiment) are provided. Furthermore, the shape of each groove 31 corresponds to the external shape of each blade 4 when viewed in the axial direction, and is provided along the extension direction of each blade 4.

[0027] As shown in FIG. 4, each groove 31 has a U-shaped cross section, including a bottom surface 32 located axially to one side of the second surface 3F and two side surfaces 33 connecting both circumferential edges of the bottom surface 32 to the second surface 3F. Of the two side surfaces 33, the first side surface 33L, which faces the first pressure surface 4L of the end portion 41 in the pre-welded state or the welded state, is located clockwise from the first pressure surface 4L and extends along the extension direction, as shown in FIGS. 4 and 6. Furthermore, of the two side surfaces 33, the second side surface 33R, which faces the second pressure surface 4R of the end portion 41 in the above state, is located counterclockwise from the second pressure surface 4R and extends along the extension direction. In the welded state, the end surface 42 of the end portion 41 is bonded to the bottom surface 32 of the groove 31.

[0028] 4, groove width H2, which is the dimension in the width direction perpendicular to both the extension direction and depth direction of each groove portion 31, is set to be larger than the plate thickness H1 of the end portion 41 of the corresponding blade portion 4 (which fits in that groove portion 31). As a result, gaps SL and SR are formed between groove portion 31 and end portion 41 in the plate thickness direction of blade portion 4. Note that in this embodiment, since plate thickness H1 of blade portion 4 is not uniform in the extension direction, the corresponding groove width H2 is also not uniform in the extension direction, and groove width H2 narrows outward from the rotation center C side.

[0029] Here, by providing groove 31 with groove width H2 wider than thickness H1 of end 41 of blade 4 as described above, blade 4 is less likely to come into contact with side surface 33 of groove 31. This reduces the dispersion of vibration energy during welding. This allows for more reliable welding of the first component 7 and the second component 8. Furthermore, burrs generated during welding can escape through gaps SL and SR formed between groove 31 and end 41. This prevents burrs generated during welding from being exposed to the ventilation passage, improving the appearance of the finished product after welding. Furthermore, this can also contribute to reducing wind noise caused by burrs generated during welding. On the other hand, by making groove width H2 of groove 31 larger than thickness H1 of end 41, backlash occurs between groove 31 and end 41 in the circumferential and radial directions. This reduces the stability of the relative positions of the two components 7 and 8 before welding, making it difficult to accurately attach the two components 7 and 8.

[0030] Therefore, the turbofan 1 of this embodiment is provided with a structure that prevents misalignment in the circumferential and radial directions between the two components 7, 8 before welding. Specifically, the turbofan 1 is provided with positioning ribs 20 (see FIG. 2 or 6 ) that partially fill two gaps SL, SR that occur on both sides of the end 41 in the plate thickness direction before welding. A set of positioning ribs 20 is provided for at least one of the multiple grooves 31 or the multiple end portions 41 of the blade portions 4. In other words, in this turbofan 1, a set of positioning ribs 20 is provided for one or more grooves 31, or a set of positioning ribs 20 is provided for one or more end portions 41 of one or more blade portions 4.

[0031] In the turbofan 1 of this embodiment, as shown in Fig. 2, a set of positioning ribs 20 is provided in each of the plurality of grooves 31 (i.e., in all of the grooves 31). As shown in Fig. 6, the set of positioning ribs 20 protrude in the plate thickness direction from the side surfaces 33 (first side surface 33L, second side surface 33R) of the grooves 31 and abut against the end portions 41 of the blade portions 4. Note that "abutting" here means a state in which the ribs come into contact with the object (end portions 41) to an extent that they do not press against the object.

[0032] In this embodiment, each set of positioning ribs 20 includes a first positioning rib 20L that protrudes from the first side surface 33L of groove 31 toward the second side surface 33R, and a second positioning rib 20R that protrudes from the second side surface 33R of groove 31 toward the first side surface 33L. In other words, each set of positioning ribs 20 includes a pair of first positioning rib 20L and second positioning rib 20R. Note that in FIG. 6, the portion where end surface 42 of end portion 41 is bonded to bottom surface 32 of groove 31 after welding is indicated by dotted lines. Also, in FIG. 6, the portion where welding rib 43 of blade 4 abuts against bottom surface 32 of groove 31 before welding is indicated by thick dotted lines.

[0033] The position at which each positioning rib 20 is provided is set, for example, near the center in the extension direction of the end portion 41. In this embodiment, the position at which each positioning rib 20 is provided is set at a position near the center in the extension direction of the end portion 41 that does not overlap with the multiple welding ribs 43, in other words, at a position that forms a gap between the multiple welding ribs 43.

[0034] The first positioning rib 20L and the second positioning rib 20R are arranged so that their normal lines NR and NL overlap at the positions where they abut against the end portion 41. That is, the first positioning rib 20L is arranged so as to overlap with the normal line NR of the second positioning rib 20R, and the second positioning rib 20R is arranged so as to overlap with the normal line NL of the first positioning rib 20L. In this way, the two (pair of) positioning ribs 20, which are provided on either side of the end portion 41, are arranged at approximately the same position in the extension direction of the end portion 41. Note that the normal lines NL and NR here are straight lines extending in a direction perpendicular to the tangent line at the positions where the positioning ribs 20L and 20R abut against the end portion 41, as viewed from the axial direction. When the protruding surface of the positioning rib 20 is inclined in the depth direction of the groove portion 31, the direction perpendicular to the tangent line at the abutting position (point, line, surface) is defined as the normal line.

[0035] Each positioning rib 20 has a shape that is, for example, a substantially semi-cylindrical shape that forms an arc when viewed from the axial direction. In other words, each positioning rib 20 is configured as a part of a cylinder having a centerline along the axial direction. Furthermore, the protruding surface of the positioning rib 20 (in other words, the peripheral surface of the substantially semi-cylindrical positioning rib 20) extends parallel to the depth direction of the groove portion 31 and the erection direction of the end portion 41 in the pre-welded state. As a result, the portion of each positioning rib 20 that protrudes most from each of the first side surface 33L and the second side surface 33R linearly abuts against each of the first pressure surface 4L and the second pressure surface 4R of the end portion 41 in the erection direction of the end portion 41.

[0036] When each positioning rib 20 is substantially semi-cylindrical, the radius of curvature is preferably as small as possible within the moldable range. The smaller the radius of curvature of positioning rib 20, the smaller the contact area between positioning rib 20 and end portion 41, thereby suppressing the dispersion of vibration energy during welding. Note that each positioning rib 20 is not limited to the above shape, and may have a shape that abuts end portion 41 in a planar manner in the erect direction of blade portion 4. By abutting end portion 41 in a planar manner, the extension direction of end portion 41 and the extension direction of groove portion 31 are more likely to coincide, thereby further suppressing oscillation of blade portion 4 before welding and during welding.

[0037] In this embodiment, the protrusion amount P1 of the first positioning rib 20L in the thickness direction is set to be equal to the protrusion amount P2 of the second positioning rib 20R in the thickness direction. In other words, the length by which the first positioning rib 20L protrudes from the first side surface 33L (protrusion amount P1) is set to be equal to the length by which the second positioning rib 20R protrudes from the second side surface 33R (protrusion amount P2). This allows the end portion 41 to be positioned at the center of the groove portion 31 in the thickness direction. In other words, the end portion 41 is positioned such that the center line of the groove portion 31 in the width direction and the thickness center line C1 of the end portion 41 are substantially aligned. Therefore, the gap SL between the first side surface 33L and the first pressure surface 4L can be formed to be equal to the gap SR between the second side surface 33R and the second pressure surface 4R. Furthermore, the end surface on the other axial side of each positioning rib 20 is positioned so as not to protrude from the respective gaps SL and SR toward the rotation center C. Here, the end surface is formed to be flush with the second surface 3F.

[0038] [2. Actions and Effects] (1) According to the turbofan 1 described above, by providing a pair of positioning ribs 20 that partially fill the two gaps SL, SR that occur between the groove 31 and the end 41, it is possible to eliminate backlash between the groove 31 and the blade 4. This improves the positioning accuracy of the first component 7 and the second component 8. Furthermore, there is no need to use a jig to position the first component 7 and the second component 8, which simplifies the assembly work. In addition, there is no need to provide through holes in the first component 7 or the second component 8 for positioning using a jig, which also helps prevent a decrease in the functionality of the turbofan 1.

[0039] Furthermore, the first positioning rib 20L and the second positioning rib 20R constituting the set of positioning ribs 20 each protrude in the plate thickness direction from the first side surface 33L and the second side surface 33R of the groove portion 31, respectively, and abut against the end portion 41. Therefore, two gaps SL and SR can be reliably formed between the groove portion 31 and the end portion 41, which makes it possible to suppress poor appearance due to the influence of burrs produced during welding and degradation of the function of the turbofan 1 due to the protruding burrs.

[0040] Additionally, in the pre-welding state, only the small positioning ribs 20 provided in the grooves 31 abut against the first pressure surface 4L and the second pressure surface 4R. The first pressure surface 4L and the second pressure surface 4R are portions (non-welded portions) not involved in welding the first component 7 and the second component 8. In other words, in the pre-welding state, only the small positioning ribs 20 provided on the second component 8 abut against the non-welded portions of the first component 7. This prevents the vibration energy generated during welding from being transmitted to the non-welded portions. Therefore, the dispersion of the vibration energy generated during welding can be suppressed. Therefore, the turbofan 1 described above can improve the positioning accuracy of the two components 7, 8 relative to each other before welding while realizing the functions of removing burrs generated during ultrasonic welding and suppressing the dispersion of vibration energy.

[0041] (2) In the turbofan 1 described above, each positioning rib 20 is located at a gap between the multiple welding ribs 43 in the extension direction of the end portion 41. In other words, each positioning rib 20 is provided at a location away from the welding rib 43, which is the portion where the groove portion 31 and the end portion 41 are welded. This makes it possible to prevent vibration energy during welding from being transmitted to the portion where the positioning rib 20 and the end portion 41 abut. This makes it possible to further prevent dispersion of vibration energy during welding.

[0042] (3) Furthermore, according to the turbofan 1 described above, the protrusion amount P1 of the first positioning rib 20L and the protrusion amount P2 of the second positioning rib 20R are set to be equal to each other, so that equal gaps SL and SR can be formed on both sides in the plate thickness direction of the end portion 41. Therefore, burrs generated during welding can be released to both sides of the end portion 41 (respective gaps SL and SR), further improving the burr release function.

[0043] (4) According to the turbofan 1 described above, each positioning rib 20 linearly abuts against end portion 41 in the erect direction of blade portion 4, thereby improving the positioning performance of positioning rib 20 for blade portion 4 (supporting force of blade portion 4). Furthermore, according to the turbofan 1 described above, in addition to being able to use positioning rib 20 as a guide when fitting blade portion 4 into groove portion 31, it is possible to maintain the erect state of blade portion 4 when fitted into groove portion 31, and it is possible to suppress oscillation of blade portion 4.

[0044] (5) Furthermore, by making each positioning rib 20 have an arc-shaped shape when viewed in the axial direction, it is possible to easily form the positioning rib 20 that makes line contact with the end portion 41. For example, when molding the second component 8 using a mold, it is difficult to form corners. However, by making the positioning rib 20 arc-shaped, it is possible to easily form the positioning rib 20 that makes line contact with the end portion 41.

[0045] (6) In the above-described turbofan 1, first positioning rib 20L and second positioning rib 20R are arranged to overlap with normal lines NR and NL at the positions where they abut against end portion 41. This allows end portion 41 to be supported from both sides at approximately the same position in the extension direction of end portion 41, thereby improving the positioning accuracy of blade portion 4 and making the attitude of blade portion 4 more stable.

[0046] (7) Furthermore, in the turbofan 1 described above, the positioning ribs 20 do not protrude from the gaps SL, SR in the direction of the rotation center C. In other words, because the positioning ribs 20 do not protrude from the gaps SL, SR in the axial direction, the air inside the turbofan 1 is less likely to be disturbed. Therefore, positioning can be performed without degrading the functionality of the turbofan 1.

[0047] [3. Other] The configuration of the turbofan 1 described in the above embodiment is an example and is not limited to the above. In the above turbofan 1, a set of positioning ribs 20 is provided in each of the grooves 31 of the second component 8, but it is sufficient that a positioning rib 20 is provided in at least one of the grooves 31.

[0048] Furthermore, when positioning ribs 20 are provided in a plurality of grooves 31 rather than in all grooves 31, it is preferable that one set of positioning ribs 20 is provided in each of two or more grooves 31 positioned at equal intervals around the center of rotation C. For example, when two sets of positioning ribs 20 are applied to turbofan 1, it is preferable that each of the two sets of positioning ribs 20 is provided in each of two grooves 31 positioned at 180 degree intervals around the center of rotation C. By providing positioning ribs 20 in grooves 31 positioned at equal intervals around the center of rotation C, the positioning accuracy of blades 4 can be further improved.

[0049] In the above-described embodiment, the arc-shaped end face on the other axial side of each positioning rib 20 is formed to be flush with the second surface 3F, but this end face may be located closer to the bottom surface 32 than the second surface 3F. The above-described effects can be obtained as long as each positioning rib 20 does not protrude at least from the gaps SL, SR toward the rotation center C. Furthermore, even if each positioning rib 20 is formed to protrude slightly from the gaps SL, SR toward the rotation center C (the other axial side), there is no problem in terms of performance of the turbofan 1.

[0050] The arrangement of each positioning rib 20 is not limited to the above. For example, the first positioning rib 20L and the second positioning rib 20R do not have to be arranged so as to overlap with the normal lines NR and NL at the positions where they abut against the end portions 41. In other words, the extension direction position where the first positioning rib 20L abuts against the end portions 41 and the extension direction position where the second positioning rib 20R abuts against the end portions 41 may be relatively largely offset from each other. For example, even if the first positioning rib 20L is arranged radially inward and the second positioning rib 20R is arranged radially outward, a pair of positioning ribs 20 can prevent the end portions 41 from being displaced. Furthermore, each positioning rib 20 may be arranged so as to overlap with the welding rib 43 in the extension direction of the end portions 41.

[0051] The shape of each positioning rib 20 is not limited to that described above. The shape of the positioning rib 20 that makes line contact with the end 41 may be, for example, a triangular prism that forms a triangle when viewed in the axial direction. Furthermore, the protrusion amount P1 of the first positioning rib 20L and the protrusion amount P2 of the second positioning rib 20R may be different from each other. For example, by making the protrusion amount of the positioning rib 20 located on the inner side of the curve of the blade 4 greater than the protrusion amount of the positioning rib 20 located on the outer side of the curve of the blade 4, the volumes of the gaps SL and SR can be made equal. This can ensure a burr-removal function equivalent to (or better than) that of the above embodiment.

[0052] A set of positioning ribs 20 may include at least two positioning ribs 20 protruding from both sides in the plate thickness direction. For example, a set of positioning ribs 20 may include a plurality of first positioning ribs 20L protruding from the first side surface 33L, or may include a plurality of second positioning ribs 20R protruding from the second side surface 33L. That is, a set of positioning ribs 20 may include, for example, two first positioning ribs 20L and one second positioning rib 20R.

[0053] Furthermore, the configuration of the blades 4 is not limited to that described above. The blades 4 do not have to have a curved shape when viewed in the axial direction. For example, the blades 4 may extend radially or may be inclined relative to the radial direction. Furthermore, the erection direction of the blades 4 may be slightly inclined relative to the axial direction. The number of welding ribs 43 is not limited to two, and three or more ribs may be provided. Furthermore, the welding ribs 43 may be omitted, or may be provided on the bottom surface 32 of the groove portion 31 instead of the end surface 42 of the blades 4.

[0054] In the turbofan 1 described above, the case where a set of positioning ribs 20 is provided in the groove 31 (in other words, in the second component 8) has been described. However, the set of positioning ribs 20 may also be provided on the end 41 of the blade 4 (in other words, in the first component 7). That is, the set of positioning ribs 20 may also be provided on the end 41 of at least one of the plurality of blades 4. In this case, the positioning ribs 20 may be configured to protrude in the plate thickness direction from each end 41 of the first pressure surface 4L and the second pressure surface 4R of the blade 4 and abut against the side surface 33 of the groove 31.

[0055] When providing a set of positioning ribs 20 on the blade portion 4, the set of positioning ribs 20 may be formed to protrude in the plate thickness direction from the first pressure surface 4L and the second pressure surface 4R not only at the end 41 but also over the entire area in the vertical direction. In this case, undercuts (convex or concave shapes that cannot be released from the mold in their original state) are not formed in the first part 7. Therefore, the first part 7 can be easily molded, and a turbofan 1 can be provided that achieves the same effects as those described above in (7) except for (7). Furthermore, if a set of positioning ribs 20 is provided over the entire area in the vertical direction of the blade portion 4 as described above, and then each positioning rib 20 is trimmed so that it does not protrude from the gaps SL and SR, the same effect as that described above in (7) can also be achieved. When providing a set of positioning ribs 20 on the blade portion 4, the first part 7 may be formed by forming the first flat surface 2 and the blade portion 4 separately and then integrating the first flat surface 2 and the blade portion 4. In addition, when a set of positioning ribs 20 is provided on the blade portion 4, the arrangement, shape and number of each positioning rib 20 may be those of the above-mentioned embodiment or those of the above-mentioned modified example.

[0056] In the turbofan 1 described above, the first component 7 has the first flat surface 2 and the plurality of blades 4, and the second component 8 has the second flat surface 3 (groove 31). However, the shapes of the first and second components that form the turbofan are not limited to this. The first component may be an annular flat surface (corresponding to the second flat surface 3) with holes for an intake airflow duct integrally formed with the plurality of blades, and the second component may have a flat surface (corresponding to the first flat surface 2) axially opposed to the annular flat surface. In this case, the plurality of grooves may be provided on the flat surface of the second component. The first flat surface 2 and the second flat surface 3 need only extend along a direction perpendicular to at least the center of rotation C, and may be slightly inclined or curved relative to that direction. [Explanation of symbols]

[0057] 1 turbofan 2 First plane part (plane part) 3 Second plane part (plane part) 4. Wing 7 First Part 8 Second part 20 Positioning rib 20L First positioning rib (positioning rib) 20R Second positioning rib (positioning rib) 31 Groove 32 bottom 33 Side 33L First side (side) 33R Second side (side) 41 End 42 End face 43 Welded rib C Rotation center NL,NR Normal H1 plate thickness H2 groove width P1 Protrusion amount of the first positioning rib (protrusion amount) P2 Protrusion amount of the second positioning rib (protrusion amount) SL,SR gap

Claims

1. A turbofan is formed by ultrasonically welding together a first component having a flat surface extending in a direction perpendicular to a rotation center and a plurality of plate-like blades standing on the flat surface and extending outward from the rotation center around the rotation center, and a plate-like second component having a plurality of recessed grooves into which the extended ends of the blades fit, Each of the grooves has a groove width wider than a plate thickness of each of the blades at the end portion, the turbofan has a pair of positioning ribs that partially fill two gaps that occur on both sides of the end portion in a plate thickness direction when the end portion is fitted in the groove portion, The set of positioning ribs each protrude in the thickness direction from the end of at least one of the plurality of blade portions and abut against a side surface of the groove portion, or each protrude in the thickness direction from the side surface of at least one of the plurality of groove portions and abut against the end of the blade portion. A turbofan characterized by:

2. each of the blade portions has a plurality of welding ribs that protrude from an end surface of the end portion and are heated when the first component and the second component are welded together; The plurality of welding ribs extend intermittently along the extension direction of the end portion, The positioning rib is located at a gap between the plurality of welding ribs in the extending direction of the end portion, or is located at a gap between the plurality of welding ribs in the extending direction of the groove portion when the end portion is accommodated in the groove portion.

2. The turbofan according to claim 1 ,

3. The positioning rib provided in one of the two gaps and the positioning rib provided in the other gap have the same protrusion amount in the plate thickness direction.

3. A turbofan according to claim 1 or 2.

4. The positioning rib is in linear contact with the side surface of the groove in the depth direction of the groove, or is in linear contact with the end portion in the erection direction of the blade portion.

3. A turbofan according to claim 1 or 2.

5. The positioning rib has an arc-shaped shape when viewed from the direction of the rotation center.

5. The turbofan according to claim 4, wherein:

6. the end of the blade portion has a curved shape when viewed from the direction of the rotation center, the set of positioning ribs are provided in the groove, The positioning rib provided in one of the two gaps and the positioning rib provided in the other gap are arranged so as to overlap with the normal line at the position where each rib abuts against the end portion.

3. A turbofan according to claim 1 or 2.

7. The positioning rib does not protrude from the gap toward the rotation center.

3. A turbofan according to claim 1 or 2.

8. The set of positioning ribs is provided on the ends of two or more of the blades positioned at equal intervals around the rotation center among the plurality of blades or on the grooves into which the ends fit.

3. A turbofan according to claim 1 or 2.

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