JP2010236493A - Manufacturing method of impeller - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of an impeller in which the impeller is manufactured so that burrs hardly remain even in an intermediate part of a blade at its completion, while being easy to manufacture, and degradation of discharge performance in the high rotation due to influence of burrs is suppressed. <P>SOLUTION: An upper surface of an unit blade plate 21 made of hard synthetic resin extending in multiple radial directions is formed as a blade end surface 21a, and on the surface an acute projection ridge 4 is situated. A truncated cone-shaped front plate 1, and a blade 2 in which the acute projection ridge 4 having a smaller width than that of the blade end surface 21a is integrally formed with an acute angle on its top end, is provided in advance. Next, an unit length volume Vs of an intermediate part in a longitudinal direction of the acute projection ridge 4 is formed smaller than an unit length volume Vs of both ends side in the longitudinal direction, and the front plate 1 is placed on the blade 2 to bring them into contact with each other. Then, an energy is applied so that temperature rises while exerting an appropriate pressing force between them, thereby the acute projection ridge 4 is melted and the front plate 1 is welded onto the blade 2. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an impeller that can be manufactured so that the burr hardly remains even at the intermediate portion of the blade when completed, and that can suppress the deterioration of the discharge performance at the time of high rotation due to the burr.

  In recent years, expectations and demands for low fuel consumption vehicles have been increasing from both an environmental viewpoint and an economical viewpoint. Various means are implemented in order to achieve low fuel consumption, and one of them is high efficiency. Whether it is a gasoline engine, a hybrid, or an electric vehicle, a water pump is attached to the vehicle for reasons such as cooling the engine or heating the vehicle interior. In response to the recent demands for lower fuel consumption and higher efficiency, water pumps are also being actively developed to achieve higher efficiency than ever.

  Some impellers of the water pump are provided with a so-called front plate. Examples of providing such a front plate include [Patent Document 1] and [Patent Document 2]. A structure in which a base plate (disc) serving as a base is provided on the base side of the blade is widely implemented as a general structure as a resin impeller. However, a hole is provided in the central portion on the tip (suction) side of the blade. In order to achieve high efficiency, an impeller structure provided with a front plate that covers the circumference of the cylinder is also widely implemented.

  Such a front plate is eventually integrated with the blade, but at the time of manufacture, a manufacturing method in which the front plate, the blade, and the base plate, which were originally separate members, are integrated is often employed. This is widely adopted as a resin impeller because of its ease of welding. Also, the background to the adoption of resin impellers is that the blade shape can be set freely compared to conventional press (sheet metal) impellers, and it is also more lightweight than press (sheet metal) impellers. It is a factor. An impeller in which the front plate is integrated with the blade (with the base plate) in this way is referred to as a “closed impeller”.

  Here, regarding the closed impeller, after explaining the shot blast for deburring, the prior art and the present invention will be described. Shot blasting is a method that is used not only for resin molded products but also for aluminum cast products, etc. Small particles of about 1 to 2 mm are vigorously applied from various angles for several tens of minutes toward the finished resin molded product. It is a method of gradually removing burrs by continuing to hit randomly.

  Although this method is widely used as a method for removing burrs from resin molded products, it is a method of removing small burrs by applying small particles from the outside of the product as a disadvantage of shot blasting. Although the burr up to the back can be removed well, there is a problem that the burr inside the product is difficult to remove because the smaller particles do not reach the farther from the product surface.

  When shot blasting is performed in consideration of the shape of the impeller with the front plate, the surface of the front plate on the anti-blade side, the surface of the base plate on the anti-blade side, the center without the front plate, the burrs on the outermost periphery of the impeller Can be removed satisfactorily, but on the blade side of the front plate and the middle part of the outer periphery and inner periphery of the donut-shaped ring plate of the front plate is covered with the front plate, and the discharge opening and blade on the blade outer periphery side Since it is located in the back away from all the suction openings on the inner peripheral side, it is a site where small particles of shot blast are difficult to reach. That is, it is difficult to remove the burr at this portion. Simply put, it is easy to remove the visible outer burr, but it is difficult to remove the invisible inner burr.

[Patent Document 1] discloses a manufacturing method and a structure in which “a member in which a front plate (front shroud 1) and a blade (blade portion 2) are integrated” and “base plate (rear surface shroud 3)” are welded. [Patent Document 2] discloses a structure and manufacturing method for welding a “front plate (cover 2)” and a “member (bottom 1) in which a blade and a base plate are integrated”.
There are many means for welding two or more resin members, not limited to resin impellers.
(1) Ultrasound, (2) Vibration, (3) Laser, (4) Hot plate, (5) High frequency, etc.

(1) The ultrasonic wave is a method in which a resin is melted and welded by applying a sound wave of about several tens of thousands of Hz to a member to be welded.
Even if ultrasonic waves are applied with the surface of the welded surface (flat surface, etc.) pressed vertically, the resin does not melt between the surfaces, so one surface is the surface, but the other surface is [Patent Document 1] FIG. 2, FIG. 4, FIG. 5, FIG. 6, FIG. 7, [Patent Document 2] FIG. 2a, FIG. 3a, FIG. 4a, FIG. 4b, FIG. 4c, FIG. As described in 5 etc., a triangular projection is provided on the welding surface. When ultrasonic waves are applied after pressing the welding surfaces of the surface and the triangular projection, the resin melts starting from the tip of the triangular projection and the welding surfaces are welded together.

(2) Vibration is a method of melting and welding resin by applying vibration of about several hundred Hz.
(3) The laser is a method of melting and welding a resin by applying a laser beam to a position to be welded.
(The above three are generally often used for welding of resin to resin.)
(4) The hot plate is a technique in which one metal or a high melting point resin is preliminarily heated to melt the low melting point resin by pressing it against the low melting point resin.
(This method can be welded with either metal or resin)
(5) The high frequency is not between the resins, but in the welding of the resin and the metal, the metal is heated by applying a high frequency to the metal, the resin is melted by pressing the heated metal against the resin by applying the high frequency, This is a welding technique. (Used only for welding resin and metal)
There are other welding methods, but the main welding methods are as described above.
The concept common to all the above welding methods is to give energy to the resin so that the temperature rises. That is, the five common operations are energy application to the resin so that the temperature rises. By such a welding method, after the resin on the welding surface is once melted, the resin melted by natural cooling is solidified and the welding surfaces are fixed to each other.

  [Patent Document 1] (Japanese Patent Laid-Open No. 53-54301) In FIGS. 4 to 7, a welding projection 4 having a triangular cross section is integrally provided on the base surface of the blade portion 2, and the rear shroud 3 is provided on the rear shroud 3. A welding groove 5 is provided. In addition, although this welding protrusion 4 and the welding groove | channel 5 have a difference of a convex and a concave, they become a corresponding (combination) shape, and are welded after combining. As described above, in [Patent Document 1], since the welding groove 5 is provided on the surface on the rear surface shroud 3 facing the base surface of the blade portion 2 to be welded by ultrasonic welding, the resin melted from the welding protrusion 4 is It collects in the welding groove 5. Therefore, there is no possibility that the melted resin protrudes from the side edge of the blade portion 2 as shown in [Patent Document 1] FIG.

  Thus, in the structure of [Patent Document 1], the presence of the welding groove 5 can prevent the molten resin from protruding, but the welding operation is performed after the blade portion 2 is accurately combined with the welding groove 5 at the time of welding. There is a need to do. If the operation of combining the blade portion 2 and the welding groove 5 is to be performed fully automatically, an image analysis device, a robot arm capable of performing fine operations, and the like are required, which results in extremely expensive equipment. On the other hand, it is possible to perform work manually, but a dedicated worker is required, and it is a considerably monotonous work, and since the surfaces other than the welding groove 5 are also flat, welding itself is possible. However, since the overall length (height) of the impeller is increased, there is a disadvantage that the impeller hits the inner surface of the casing or the flow path becomes narrow accordingly. In such a case, if it cannot be welded, it is immediately determined that it is a manufacturing defect. However, since it can be welded, it becomes clear after attachment or a strict inspection is required.

  [Patent Document 2] (US Pat. No. 5,538,395) describes FIG. As described in 2 a, 3 a, 4 a, 4 b, 4 c, 5, a structure is disclosed in which a triangular protrusion is provided on the tip surface 14 of the blade 11 and is ultrasonically welded to the cover 2. When the shape of the triangular protrusion in [Patent Document 2] is further observed, the triangular protrusion is disposed over the entire area in both the width direction and the length direction with respect to the tip surface 14 of the blade 11. Yes. In other words, the entire tip surface 14 is covered. When welding is performed in this shape, since [Patent Document 2] is not provided with a groove as in [Patent Document 1], as shown in FIG. 2 (b) of [Patent Document 1]. It is inevitable that the molten resin protrudes. In particular, burrs in the middle part of the blade are difficult to remove even by the above-described shot blasting and may remain even in a completed state. When the resin protrudes as described above, there are the following problems.

  Although the fluid flows through the impeller, since it is a place where the fluid flows, the impeller has a continuous continuous curved surface so that the flow is not disturbed. The presence of a convex part called a burr in such an impeller causes a disturbance in the flow starting from that part. When the rotational speed is low, the influence is not so great. However, as the rotational speed increases, cavitation is likely to occur from the burr portion, so that the discharge performance at high rotational speed is greatly reduced.

  Furthermore, it is conceivable that the burr is dropped while being used for a long time and circulated in the cooling water circuit. Since this burr is a small one of about 1 mm or less, if it bites into the drive part of another part in the cooling water circuit, the operation of the other part may be adversely affected. In order to avoid such a problem, if a groove corresponding to the shape of the blade tip surface is provided on the front plate side, burrs are not generated, but the manufacturing difficulty increases and the impeller price becomes expensive. If the groove is not provided, manufacture becomes easy, but burrs that cannot be removed by the above-described shot blasting remain in the blade intermediate portion, leaving room for improvement in terms of performance and reliability.

JP-A-53-54301 US Pat. No. 5,538,395

  As described above, the improvement of the efficiency of the impeller (impeller), which is important along with the flow path, has been developed and implemented as an improvement in the efficiency of the water pump. Furthermore, recently, there has been an increasing demand for cost reduction of vehicles by users, and in response to this, the present invention proposes a method for achieving high efficiency at a low cost. The problem (technical problem or purpose) to improve the impeller (impeller) manufacturing method, which is important along with the flow path, is easy to manufacture but does not leave burrs even in the middle part of the blade when completed, It is possible to avoid a drop in discharge performance at high rotation due to the influence of burrs, and to realize a cost reduction request.

  Accordingly, as a result of intensive researches to solve the above-mentioned problems, the inventor has changed the invention of claim 1 from the top surface of a truncated conical front plate and a unit blade made of hard synthetic resin extending in a plurality of radial directions. As a blade tip surface, and a blade formed integrally with a sharp ridge on the blade tip surface and having a width smaller than the width of the blade tip surface and having an acute angle at the upper end, the length of the sharp ridge The unit length volume of the intermediate portion in the direction is formed smaller than the unit length volume at both ends in the longitudinal direction, the front plate is placed on the blade, and the sharp ridge end and the front The lower surface of the plate is brought into contact, and energy is applied so as to increase the temperature while applying an appropriate pressing force between the front plate and the blade, the sharp protrusion is melted, and the front plate is welded to the blade. To do By the impeller manufacturing method of the symptoms, to solve the above problems.

  The invention according to claim 2 is the method of manufacturing an impeller according to claim 1, wherein both ends of the sharp protrusion are formed to have the same height while the intermediate portion is formed to be low. The above-mentioned problem has been solved. According to a third aspect of the present invention, in the first aspect, while forming the same height over the entire length of the sharp ridge, both ends thereof have the same width, and the intermediate portion is formed to have a narrow width. By solving the above-described problem, the above-mentioned problem has been solved. According to a fourth aspect of the present invention, in the first aspect, the both ends of the sharp ridge are made to have the same height, and the intermediate portion is formed so as to have a non-existing region or a comb-like portion. By solving the above-described impeller manufacturing method, the above-mentioned problems are solved.

  In the first aspect of the present invention, firstly, although it is easy to manufacture, it can be manufactured so that burrs do not remain even in the blade middle part at the time of completion, and secondly, the discharge performance at the time of high rotation due to the burr is reduced. This is an invention that can be avoided, and thirdly, can achieve cost reduction. In the present invention, focusing on the fact that the welding strength is not required as much as the outer peripheral part and the inner peripheral part in the blade intermediate part that is difficult to remove burrs by shot blasting, the unit length volume (protrusion amount) of the sharp ridge in the blade intermediate part is determined. By making it less than the outer peripheral part and inner peripheral part, burr was not left in the middle part of the blade. In this way, burrs on the outer peripheral part and the inner peripheral part can be removed by shot blasting, so that the finished product can be molded so that no burrs remain.

  In the present invention, all burrs are removed from the finished product, but the welding strength can be ensured by providing sharp protrusions (protrusions) large enough to generate burrs once on the outer peripheral portion and inner peripheral portion where welding strength is required. . In the present invention, since burrs do not remain, turbulent flow and cavitation are less likely to occur, and there is the greatest advantage that discharge performance can be ensured particularly at high rotations. In addition, the front plate of the present invention does not require a groove having a shape such as that of [Patent Document 1] combined with the blade front end surface, so that it is not necessary to manage the front plate phase (angle), and an appropriate phase (angle). Then set the front plate and weld it to complete the product. That is, the labor and equipment costs of the worker are minimal. Further, in the invention of claim 2, the intermediate portion of the sharp ridge can extremely reduce the occurrence of burrs, and both ends can be firmly welded. The invention of claim 3 has the same effect as the invention of claim 2. The invention of claim 4 can also exhibit the same effect as that of the invention of claim 1.

(A) is a plan view in which the front plate is welded to the blade with the base plate, and (B) is a cross-sectional view in which the front plate is welded to the blade with the base plate. -X1 arrow sectional view, (C) is an enlarged view of (A) part of (B), (D) is an X2-X2 arrow sectional view of (A) (cross sectional view passing through the cone apex), (E). FIG. 5 is a cross-sectional view of a front plate that has been welded to a blade with a base plate. (A) is an enlarged plan view of the unit blade, (B) is a front view of the top portion of the unit blade as viewed from the arrow Y1-Y1 of (A), and (C) is an enlarged view of (a) of (A). It is a perspective view. (A) is an enlarged plan view of a unit blade according to another embodiment, (B) is a front view of the top portion of the unit blade as viewed from the arrow Y2-Y2 in (A), and (C) is (C) in (A) FIG. (A) is an enlarged plan view of a unit blade according to another embodiment, (B) is a front view of the top portion of the unit blade as viewed in the direction of arrows Y3-Y3 in (A), and (C) is (A) ( D) Enlarged perspective view of the part. (A) is an enlarged plan view of the unit blade according to another embodiment, (B) is a front view of the top portion of the unit blade as viewed in the direction of arrows Y4 to Y4 in (A), and (C) is ( E) Enlarged perspective view of the part. (A) is a cross-sectional view of the state in which the front plate is in contact with the sharp ridge at the top of the blade as viewed in the direction of the arrow ZZ in FIG. 7, and (B) is a state in which the front plate is brought into contact with the sharp ridge at the top of the blade and pressed. FIG. 4C is a cross-sectional view of the present invention at the initial and middle stages of welding while being welded, and FIG. 5C is a cross-sectional view of the present invention at the final stage of welding while pressing the front plate against the sharp protrusion at the top of the blade and pressurizing. . It is the partial top view which looked at the unit blade board from the top of the front plate.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. Reference numeral 1 denotes a front plate, which is a truncated conical (trumpet-shaped) annular plate. When viewed from a cross-section, a circular (ring) plate having a convex shape whose upper side is constricted with respect to the vertical axis n, and whose height decreases toward the outer periphery, with a circular hole 1a at the center. The thickness is about 1 to 2 mm, and the material is a hard synthetic resin material. In the first embodiment, the front plate 1 is a flat trumpet-shaped annular plate obtained by cutting off the top of an arbitrary cone. That is, the first embodiment will be described as a conical type. A cone apex angle (also referred to as a solid angle) at a virtual apex portion of the inner surface 1b (lower side in FIG. 1B) of the conical surface of the front plate 1 is assumed to be φ (see FIG. 1B).

  Reference numeral 2 denotes a blade, and a base plate 3 which is a disc is integrally formed below the blade. Such a member is referred to as a blade 2 with a base plate 3. In the blade 2, a base portion of a plurality of unit blade plates 21, 21,... Is integrally formed on the outer periphery of a cylindrical piece-like boss portion 22. The boss portion 22 includes a metal boss portion main body 22a having a through-hole formed in the center portion, and a thick portion 22b on the outer peripheral side with respect to the boss portion main body 22a. The thick portion 22b is formed so that the base of the unit blade 21 and the central portion of the base plate 3 are integrated. That is, the blade 2 except the metal boss main body 22a and the base plate 3 are made of a hard synthetic resin material made of the same material. It is formed as an axis m of the blade 2 with the base plate 3.

  In the unit blade plate 21, the side opposite to the fixing side of the base plate 3 is [upper side in FIG. 1B] as a blade tip surface 21 a corresponding to the shape of the front plate 1. Has become a department. More specifically, the blade tip surfaces 21a, 21a,... Of the unit blade plates 21, 21,... Constituting the blade 2 are the same as the cone apex angle φ of the inner surface 1b (lower surface) of the front plate 1. Is formed as a part of a conical surface having a cone apex angle φ. On the upper side of the blade tip surfaces 21a, 21a,... The sharp ridge 4 has a triangular cross-section, the tip (upper end) is an edge with an acute angle, and the lower surface is a part of the blade tip surface 21a in the width direction, and the unit It is integrally formed with the blade 21. 1 is a line passing through the rotation center O of the unit blade plate 21 and the section of the unit blade plate 21 itself is usually hatched. In order to distinguish from the base plate 3 or the like, the cross section processing is not performed. The rotation center O and the cone apex coincide with each other on the axis m.

  The height H of the sharp ridge 4 (height from the blade tip surface 21a) is substantially uniform in part [see FIG. 1 (D)]. Further, the shape of the sharp ridge 4 viewed in a plane is not limited as long as it is a shape that does not cover the entire surface of the blade tip surface 21a. That is, it is provided at about 1/4 to 3/4 of the width of the blade tip surface 21a. If the width is narrow, the welding strength cannot be secured, and if the width is too wide, the effect of the present application cannot be exhibited. Preferably, it is provided at ½ or less of the width of the blade tip surface 21a. More preferably, the sharp ridge 4 is formed at a substantially central position of the width thereof, and in particular, the sharp ridge 4 gently disappears at both end portions when the unit blade plate 21 is viewed in plan. It is formed [see FIG. 2 (A)]. Further, both ends of the sharp ridge 4 are formed so as to disappear gently even when viewed from the front [see FIGS. 2B and 2C].

  Specifically, the sharp protrusion 4 has a protruding height of about 0.3 mm to about 0.8 mm as a protrusion having a triangular cross section. Furthermore, the shape of the triangular protrusion when the resin melts out, but the tip of the sharp protrusion 4 has a higher sensitivity as a starting point where the resin melts when the tip is an acute edge. The part is preferably an acute edge. By the way, it is the shape of the embodiment of the present invention that the sharp ridge 4 is variously deformed. A configuration that appropriately reduces the amount of protrusion at the intermediate portion in the longitudinal direction of the sharp protrusion 4 is the essential content of the invention.

  That is, even if the amount of triangular protrusions in the intermediate portion of the sharp protrusion 4 is reduced, there are various shapes at the stage of implementation. The upper level conception is captured by the unit length volume Vs. In this specification, the unit length volume Vs means a volume per unit length in the longitudinal direction of the sharp protrusion 4. Then, the outline of the present invention is configured such that the unit length volume Vs of the intermediate portion in the longitudinal direction is smaller than the unit length volume Vs of both ends in the longitudinal direction of the sharp protrusion 4.

  As an embodiment of the present invention, a type in which the height H is lowered as the first embodiment [see FIGS. 2A to 2C], and a type in which the width L is narrowed as the second embodiment [FIG. 3A]. Thru | or (C)], comb type as a 3rd embodiment [refer to Drawing 4 (A) thru / or (C)], removal type as a 4th embodiment [refer to Drawing 5 (A) thru / or (C)], and further As long as the amount of triangular protrusions at the intermediate portion of the sharpened protrusion 4 is reduced from both end portions in the longitudinal direction, the present invention is not limited to the embodiment.

  As shown in FIGS. 2A to 2C, in the type in which the height H is reduced as the first embodiment, the sharp ridge 4 on the blade tip surface 21a of the unit blade plate 21 is in the longitudinal direction. The intermediate low portion 4b in the longitudinal direction has a shape in which the height H is lower than both end portions 4a and 4a. The width L is constant over the entire length. At the time of actual welding, the front plate 1 is pressed against the tip of the sharp protrusion 4 on the blade tip surface 21a, and welding is performed using ultrasonic welding means (giving energy that increases the temperature). When the front plate 1 is pressed against the tip of the sharp ridge 4, the tip of the sharp ridge 4 of the middle low portion 4b is set to a height that does not contact the front plate 1 [see FIG. 6 (A)]. Each of FIGS. 2A to 5A is a plan view that rotates clockwise (arrow direction) about the rotation center O of the unit blade 21.

This means that it does not come into contact at the start of welding, and as the welding proceeds, all the sharp ridges 4 are finally melted, so that the sharp ridges 4 of the intermediate low portion 4b come into contact with the front plate 1 from the middle. . Further, the sharp protrusion 4 at the intermediate low portion 4b is smaller than both end portions 4a and 4a of the outer peripheral portion or the inner peripheral portion, the welding strength is low, and the occurrence of burrs is zero or nearly zero. It has become. In FIG. 2 (B), the height H of both end portions 4a, 4a of the outer peripheral portion and the inner peripheral portion is the same, but as another embodiment of the present invention, the height of the protrusion of the sharp ridge 4 is
The intermediate low portion 4b <the inner peripheral portion (end portion 4a) <the outer peripheral portion (end portion 4a) may be used. Further, in the embodiment shown in FIGS. 1 and 2, the both end portions 4a and 4a and the intermediate low portion 4b rapidly change in height, but may be formed so as to change gradually.

  As shown in FIGS. 3A to 3C, in the type in which the width L is reduced as the second embodiment, the sharp protrusion 4 on the blade tip surface 21a of the unit blade plate 21 has a uniform height H. In addition, the intermediate portion is formed as an intermediate thin portion 4c having a width narrower than the width L of both end portions 4a, 4a in the longitudinal direction. Since the height H of the sharp ridge 4 is uniform, the sharp ridges 4 in all longitudinal directions are melted at the same time, and as shown in FIG. This burr is a dotted line portion that bulges on both ends. Such end portions 4a and 4a can be easily deburred by shot blasting.

  Further, as shown in FIGS. 4A to 4C, in the comb-tooth type as the third embodiment, the sharp ridges 4 on the blade tip surface 21a of the unit blade plate 21 are both end portions in the longitudinal direction. 4a, 4a is formed as a predetermined height H, and a plurality of protruding pieces are provided in the middle in the longitudinal direction to form a comb-like portion 4d and the same as the predetermined height H of both end portions 4a, 4a Configured. Thereby, the unit length volume Vs of the intermediate part in the longitudinal direction is formed small. Further, as shown in FIGS. 5A to 5C, the removal type as the fourth embodiment is formed as a predetermined height H of both end portions 4a, 4a in the longitudinal direction, and in the intermediate portion in the longitudinal direction, A protrusion non-existence region 4e is provided. In this non-existing region 4e, the welding strength with the front plate 1 is almost zero, and no burrs are generated. In this case, it is fixed by the welding strength at both end portions 4a, 4a.

  A method for welding the front plate 1 to the blade 2 will be described. In FIG. 6A, the front plate 1 is placed on the blade 2 with the base plate 3 (unit blade plate 21) from above, and the lower surface of the front plate 1 and the sharp ridges 4 of the blade tip surfaces 21a, 21a,. 4. Apply energy to raise the temperature with ultrasonic waves etc. while contacting and applying pressure. Then, as shown in FIG. 6 (B), the edges of the tip portions of the sharp ridges 4, 4,... Of the blade tip surfaces 21a, 21a,. The edge is only the starting point of melting, and once melted, the sharp ridges 4, 4,... Continue to melt as the energy is applied while being pressurized. The lower surface of the front plate 1 hits the blade tip surface 21a [see FIG. 6C], and when there is a lot of molten resin, it flows out to the unit blade plate 21 side. When the triangular pointed protrusions 4, 4,... Are completely melted [see FIG. 6C], the resin hardly melts any more and the front plate 1 is welded to the blade 2 at the same time. . Note that the present application is an invention relating to welding strength and burrs, focusing on the sharp protrusion 4, and is not limited to the five welding methods disclosed as long as the means provides energy that raises the temperature.

  As another viewpoint, the operation of the impeller will be described. In the impeller to which the front plate 1 is welded, a circular hole 1 a is provided at the center of the front plate 1 to form a suction hole, and the fluid sucked from the suction hole is a region sandwiched between the front plate 1 and the base plate 3. Is moved outward in the centrifugal direction while being pushed in the rotational direction by the blade 2. At the outermost periphery of the blade 2, the front plate 1 and the base plate 3 are also the outermost periphery having the same diameter, and fluid is discharged from the discharge opening to the outside of the impeller in the centrifugal direction. The impeller is one object, and the rotation speed is the same on the inner peripheral side and the outer peripheral side of the impeller. Since the inner diameter side and the outer diameter side have different diameters, the peripheral speed is proportional to the diameter. The force from the fluid received by the blade 2 also increases in proportion to the peripheral speed. For this reason, the largest force is applied to the outer peripheral side of the impeller.

  By the way, I will give a simple analogy. Assuming that the objects A and B of a predetermined length have been attached, when trying to peel them off, they are generally peeled off from the end and pulled from the middle part. It is extremely difficult to remove. The same applies to the welded impeller and the front plate 1 as in the present invention. Even if the phenomenon in which the weld is peeled off and the front plate 1 falls off is considered, if the front plate 1 falls off, the end ( The outer peripheral end or the inner peripheral end) is peeled off, and the possibility of peeling off from the blade intermediate portion is very low.

  Thus, it is the outer peripheral end that requires the most strength for welding the front plate 1. The outer peripheral end has the largest applied force and is easily peeled off. Next, it is the inner peripheral edge that requires welding strength. The inner peripheral edge is small in force, but easily peels off. It is the blade middle part that does not require much welding strength. This is because the blade cannot be peeled off from the middle part of the blade unless the end is peeled off.

  As described above, it is also the middle part of the blade that the burr is hardly removed by shot blasting. When the welding is examined, the welding strength becomes almost zero when the sharp ridge 4 on the blade tip surface is very small or not at all, and the welding strength increases as the sharp ridge 4 increases. On the contrary, burrs do not occur if there is no sharp protrusion 4 on the blade tip surface 21a, and the molten resin does not protrude from the blade tip surface 21a at a certain projection size, so it does not become burrs. If it is larger than a certain level, the molten resin protrudes and becomes burrs. In other words, there is no burr at a certain size of the sharp protrusion 4, and the burr increases as the protrusion increases.

  Considering the above characteristics, the outer peripheral portion of the blade 2 is a portion that requires the most welding strength, and at the same time, a portion where burrs can be removed by shot blasting. Therefore, the sharp protrusion 4 on the blade tip surface 21a is enlarged. Further, the inner peripheral portion of the blade 2 is not as large as the outer peripheral portion, but is a portion that requires welding strength and is a portion where burrs can be removed by shot blasting. Therefore, the sharp protrusion 4 on the blade tip surface 21a is also enlarged. The intermediate portion of the blade 2 does not require so much welding strength, and is a portion where burrs are difficult to remove by shot blasting, so the sharp ridge 4 on the blade tip surface 21a is made smaller than the inner and outer peripheral portions, The variations are as described above.

  Unlike the technical contents of [Patent Document 1], the configuration is as described above, but as the effect of the present application, all the burrs are removed from the finished product while ensuring the welding strength. There are no grooves. As the cross-sectional shape of the front plate 1 and the cross-sectional shape of the unit blade plate 21 taken along X2-X2 in FIG. 1A, a conical type that decreases linearly is common. Further, the front plate 1 and the blade 2 (impeller body) are made of the same material. Further, if a welding method such as (4) hot plate or (5) high frequency is used, a metal such as aluminum can be used. When the metal such as aluminum is used, the same strength as the resin can be achieved with a thin plate thickness, and therefore the blade 2 (flow path) can be enlarged by the amount that the plate thickness can be reduced.

  The shapes of the front plate 1 and the blade tip surface 21a are the contents of a conical surface. In the first embodiment of the present invention, a cone whose bus is a straight line is applied. In this specification, the surface portion of the cone is referred to as a “conical surface”. Furthermore, a cone having a generatrix (curved) as a generatrix is referred to as an “arc cone”, and a surface portion of the arc cone is referred to as an “arc cone surface”. Furthermore, the superordinate concept of a cone and an arc conical is called “conical”, and the superordinate concept of a conical surface and an arc conical surface is called “conical surface”. As the shapes of the front plate 1 and the blade tip surface 21a, the arc cone is applied to an arc cone type in which the middle of the cross-sectional arc is recessed inward and a type in which the middle of the cross-section arc bulges outward. In any of the embodiments, if the blade tip surface 21a and the corresponding cone apex angle φ of the front plate 1 are the same, the center position can be obtained by “centering action” if the structure is welded by slight vibration. A highly accurate impeller can be manufactured by matching these.

DESCRIPTION OF SYMBOLS 1 ... Front plate, 1b ... Inner surface, 2 ... Blade | wing, 21 ... Unit blade | wing plate,
21a ... blade tip surface, 3 ... base plate, 4 ... sharp ridge, 4a ... end portion,
4b ... middle low part, 4c ... middle thin part, 4d ... comb tooth-like part, 4e ... non-existing region,
Vs: Unit length volume.

Claims (4)

  A top surface of a truncated conical front plate and a unit blade made of hard synthetic resin extending in a plurality of radial directions is formed as a blade tip surface, and is on the blade tip surface and smaller than the width of the blade tip surface. A blade integrally formed with a sharp ridge having a width and an upper end having an acute angle, and the unit length volume of the intermediate portion in the longitudinal direction of the sharp ridge is smaller than the unit length volume on both ends in the longitudinal direction. The front plate is placed on the blade to bring the sharp ridge end into contact with the lower surface of the front plate, and a temperature is applied while applying an appropriate pressure between the front plate and the blade. The impeller manufacturing method is characterized in that energy is applied so as to rise, the sharp ridge is melted, and the front plate is welded to the blade.   2. The method of manufacturing an impeller according to claim 1, wherein both ends of the sharp ridge are formed to have the same height while the intermediate portion is lowered.   2. The impeller according to claim 1, wherein the sharp ridges are formed to have the same height over the entire length, and the intermediate portions are formed to have a narrow width while the both ends thereof have the same width. Manufacturing method.   2. The method of manufacturing an impeller according to claim 1, wherein both ends of the sharp ridge are formed at an equal height, and the intermediate portion is formed so that a non-existing region or a comb-like portion exists.

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