JP2000120587A - Blade structure of forward-curved multiblade centrifugal blower impeller and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To stably mass-produce a light and homogeneous blade having high rigidity, and good dynamic balance by arranging positioning holes of an injection molding process on both end parts of a blade attaching part, and positioning and fixing the blade attaching part in a mold utilizing upper and lower positioning pins of the mold. SOLUTION: In the case where a blade is manufactured in a both suction forward-curved multiblade centrifugal blower impeller, a raw material of a blade attaching part 1 is made of galvanized sheet iron, a blade part 2 is made of ABS resin. Each positioning hole 3 is arranged on an inside from blade part X and Y surfaces 11, 12 of both end parts of a blade by about 10 m/m, and the blade attaching part 1 is fixed to a mold by a pair of upper and lower positioning pins with flanges. A center positioning hole 4 for fixing a back plate is arranged on a center part, and is fixed to the mold by a pair of upper and lower positioning pins with flanges. Two opening parts 5 are arranged on right and left sides of the blade attaching part 1, a gate is arranged corresponding to the opening parts 5, resin is filled, and a blade part 2 is integratedly molded.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a blade of a forward multi-blade centrifugal blower impeller used for devices such as air conditioning, ventilation, exhaust, and equipment cooling, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Heretofore, when the impellers belonging to this technical field are classified from constituent materials, the material excluding the boss is made of any single material such as metal or plastic. As a result, the inherent disadvantages of the material could not be covered, and satisfactory performance could not be obtained.

The present inventor has invented a structure of a centrifugal blower impeller which makes use of the features of both metallic and non-metallic materials and compensates for both disadvantages, and a method of manufacturing the same. U.S. Pat. No. 5,476,365 and Japanese Patent Application No. 5-263122 are examples thereof.

[0004] However, in the blade production process by the outsert injection molding method described in detail in the above-mentioned prior application as one of the embodiments, the structure of the blade mounting portion has some defects, Mass production quality could not be obtained. The present application seeks to eliminate that defect. Also, the so-called
Since the outsert injection molding method has been adopted for the mass production method, it is still young and technically unsolved. For relatively small parts such as electronic parts, see Japanese Patent Application No. 5-761.
No. 11, Japanese Utility Model Application No. 5-32707, etc. have been filed in the prior application, but there is almost no technology for medium and large objects as in the present application.

[0005]

A non-metallic (for example, plastic or synthetic resin) wing is attached to a metal wing mounting portion.
In the construction method of so-called outsert injection molding,
The problems to be solved are the following four points.

The first problem is that, due to the injection pressure of the resin, the metal blade mounting portion moves from a regular position in the mold, and the mass production quality varies. Is a great loss of quality.

The second problem is that, depending on the injection pressure of the resin,
The metal wing mounting portion is deformed, and as in the first problem, the dynamic balance quality of the assembled impeller is greatly impaired.

The third problem is a so-called mold seal leak in which resin leaks from a contact portion between a metal wing mounting portion and a mold.

The fourth problem is that since the expansion ratios of the metal material and the non-metal material are greatly different from each other, a tensile stress remains in the wing portion after the outsert molding, and the outer surface of the wing portion, or a sharp metal cut surface and the resin are not bonded. From the contact portion.

[0010]

According to the present invention, such a problem has been solved by improving the structure of the blade mounting portion and setting injection conditions. Means 1, 2, 3, and 4 will be described below corresponding to the tasks 1, 2, 3, and 4, respectively.

Means 1. Positioning holes for the injection molding process are provided at both ends of the wing mounting portion, and the wing mounting portion is three-dimensionally positioned and fixed in the mold by special positioning pins in the upper and lower dies of the mold. . It is also effective to provide an auxiliary positioning hole. The auxiliary hole is positioned by an auxiliary positioning pin, and receives a load from a side opposite to a load direction of the injection pressure by a flange of the auxiliary pin. The opposite surface of the auxiliary positioning pin is filled with resin and does not penetrate. By this means, the position of the blade mounting portion in the mold is determined, and the movement of the blade mounting portion due to the injection pressure of the resin is further prevented. The positioning holes at both ends are set at locations where there is no problem in performance even if they penetrate after molding.
This will be described in detail in Examples. The effect of the auxiliary non-through hole is small if the diameter is small, and almost negligible if the position is at the back and rear of the forward facing blade.
The cross-sectional shape of the wing mounting part is most preferably along a curved surface similar to the wing part. However, if it is necessary to increase rigidity with respect to the resin injection pressure, it is bent in one or several places in parallel with the longitudinal direction. May be added.

Means 2. In order to reduce the injection pressure of resin,
An opening is provided between the center and both ends of the wing mounting portion. It is best if the gate is provided corresponding to the space. or,
In order to reduce the flow pressure inside the resin mold, it is preferable that the four sides or edges of each opening be extended or bent to make the end face round as shown in FIG.

Means 3. In ordinary injection molding, the problem can be almost neglected. In the case of outsert injection molding, this is a major problem. That is, since the end of the part (the wing mounting portion in the present case) outsert from the inside of the injection molding die goes to the outside of the die, there is a gap between the die and the end of the wing mounting portion at this contact portion. If there is, resin leaks. For this reason, the shape accuracy of the end of the blade attachment portion in this contact portion is strictly required. In the present application, as shown in FIG. 7, the end shape of the wing mounting portion is obtained by rolling the raw materials from both sides and superimposing them, and further adding a recoiling process during the press working process to secure the outer shape accuracy. When a gap of about several hundredths of a millimeter is provided on the inner contact surface of the superposed materials, the accuracy of the outer shape is improved, and leakage of the resin can be further prevented.

Means 4. First, the cut surface of the wing mounting portion is bent or turned so that the press cut surface having a sharp edge does not come into contact with the non-metal wing portion to reduce the notch effect. Further, immediately before the molding step, the blade mounting portion is heated to near the resin injection temperature, set in a mold, and then molded. After forming, the composite blade is removed from the mold and, during the course of natural cooling, the metal wing mount shrinks more than the non-metal wing profile, and thus compressive stresses are created within the wing profile. The time crack is eliminated by the reduction of the notch effect of the wing mounting portion and the presence of the compressive stress in the wing shape portion.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION

[0016]

Embodiment 1 Preferred Embodiment 1 of the present invention will be described in more detail with reference to the drawings. FIGS. 1 to 7 show a double-suction forward-facing multiblade centrifugal blower impeller (diameter 284 m / m, width 12
0m / m, 48 blades, blade arc length 29m / m
-It is explanatory drawing of the blade of a back plate (center part). The material of the wing mounting part is galvanized steel sheet, thickness 0.6m /
m, the wings are made of ABS resin. One positioning hole 3 (4 m / m in diameter) is provided at 10 m / m inside the blade from the wing X surface 11 and the Y surface 12 at both ends of the blade, and as shown in FIG. / M) and is fixed to the mold by a pair of upper and lower positioning pins. Since both suction impellers are used, a center positioning hole 4 (3 m / m in diameter) is also provided in the center for fixing the back plate, and a collar (5 m / diameter) is provided.
m) and fixed to the mold with a pair of upper and lower positioning pins. That is, the wing mounting portion is fixed to the mold by the three positioning pins. Although this portion remains as a through hole without being filled with resin even after injection molding, it has been confirmed by an experiment that the performance is not affected as long as the inside is within 15 m / m at both ends. The setting range of the through-hole which does not affect the blower performance differs depending on the diameter of the impeller, and thus is confirmed by experiments. Also, since the through hole in the center part is almost closed after the back plate is fixed, this also does not affect the performance. Since the blade length is relatively short at 120 m / m in the blade longitudinal direction with respect to the blade arc length of 29 m / m, four openings 5 are provided on the left and right at a total of four locations. This opening 5
It is also effective to provide a gate in response to the above, to prevent the blade mounting portion from receiving the injection pressure of the resin and being deformed. The opening 5 is set in the blade longitudinal direction 30.
It is provided at a rate of one place from m / m to 50 m / m. When the injection pressure applied to the wing mounting portion is large and the wing mounting portion is deformed or moves in the mold, an auxiliary positioning hole 6 is provided between the openings, as shown in FIG. In this way, support from one side with an auxiliary positioning pin with a flange. In this case, it is preferable that the gate position is set so that the resin injection pressure is exerted in the direction from the front surface to the rear surface of the blade at the blade mounting portion, and the blade mounting portion is supported from the rear surface of the blade. The auxiliary hole 6 is not formed as a through hole since the opposite surface of the auxiliary positioning pin is filled with resin. If the filling surface is set to the front surface of the blade, holes for auxiliary positioning pins remain on the rear surface, but small holes on the rear surface of the blade hardly affect blower performance.

The flange of the positioning pin with a flange does not need to have a round shape. The point is that the wing mounting section should be fixed in the mold in three dimensions.

Since the outer side 9 of the wing mounting portion and the inner four sides 10 of the opening 5 are bent or bent as shown in FIG. 4, the resistance to the injection pressure of the resin and the rigidity are high. The deformation and displacement of the wing mounting portion can be prevented. As described above, since all edges in contact with the resin do not have a sharp edge, the notch effect is eliminated, and the timing cracking phenomenon is almost eliminated. In addition, one side or two sides of the wing mounting portion may be extended without being bent for reasons such as improvement in rigidity of the wing portion. However, as shown in FIG. R
When the surface is processed by pressing, the notch effect is reduced. Even with such measures, there is still a tensile stress,
Although there is a possibility of cracking at a slight time, it is also effective to heat by high frequency heating or the like before the forming step as described above.

The wing mounting portion is continuously pressed from the coil material by a progressive die, but there is also an example in which the feed bar is not cut but diverted as it is to the end ring of the impeller. The details are described in 5-263122. In this application, a description will be given of the most general method of assembling an impeller. FIG.
The wing mounting shown in FIG. The tab 8 at the end of the end portion 7 is inserted into a tab hole of an end ring (not shown) and fixed by caulking or the like to form a cylindrical body. A back plate is inserted into the cylindrical body, and the central portion is inserted. If fixed by caulking, etc. (Japanese Patent Application No. 5-2
63122), and the impeller is completed.

[0020]

Embodiment 2 Preferred embodiment 2 of the present invention will be described in more detail with reference to the drawings. FIG. 11 shows a single suction front-facing multi-blade centrifugal blower impeller (diameter 284 m / m, width 60 m / m).
It is an explanatory view of a blade having 48 blades and a blade arc length of 29 m / m). The material of the wing attachment part is a galvanized steel plate and a thickness of 0.6 m / m, and the wing part is ABS resin. Since it is a single-suction impeller, if a through hole exists on the disk side of the blade, the performance is greatly impaired. Therefore, the positioning holes 13 and 14 (diameter 4 m / m) are formed from the wing end surfaces 15 and 16 at both ends of the blade. It is provided at one place each on the outside, and is positioned on the mold by positioning pins. Blade arc length 29m
/ M, which is relatively short at 60 m / m in the blade longitudinal direction, so that the number of openings is two. In some cases, an auxiliary positioning hole is provided between the openings, and the auxiliary positioning pin with a flange is supported from one side as shown in FIG. Since the positioning holes are outside the wings, when the injection pressure in the injection molding process cannot be sufficiently satisfied, the number of auxiliary holes is increased by several. If both ends (tabs) are inserted into the tab holes of the end ring and the disc and fixed by caulking or the like, a single-suction multi-blade blower impeller is completed. This type of impeller is common and will not be described in detail herein.

[0020]

As described above, according to the present invention, a uniform blade can be stably mass-produced, and is lightweight, high rigidity,
An impeller with good dynamic balance can be obtained.

[Brief description of the drawings]

FIG. 1 is a front view of a blade according to a first embodiment of the present invention. The area surrounded by the two-dot chain line is the wing.

FIG. 2 is a rear view of the blade according to the first embodiment of the present invention.

FIG. 3 is a sectional view of the blade AA according to the first embodiment of the present invention.

FIG. 4 is a sectional view of the blade BB according to the first embodiment of the present invention.

FIG. 5 is an enlarged cross-sectional view of the blade CC of Example 1 of the present invention.

FIG. 6 is a cross-sectional view of the blade DD according to the first embodiment of the present invention.

FIG. 7 is a sectional view of the blade EE according to the first embodiment of the present invention.

FIG. 8 is an application example diagram of a BB cross section of the first embodiment of the present invention.

FIG. 9 is an enlarged explanatory view of an auxiliary positioning pin according to the first embodiment of the present invention.

FIG. 10 is an explanatory diagram of a positioning pin according to the first embodiment of the present invention.

FIG. 11 is a front view of a blade according to a second embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Wing mounting part 2 Wing part 3 Hole for positioning both ends of wing mounting part 4 Center positioning hole of wing mounting part 5 Opening of wing mounting part 6 Hole for auxiliary positioning of wing mounting part 7 End face of wing mounting part 8 Tab 9 Outer side of wing mounting part 10 Inner four sides of opening of wing mounting part 11 Wing end face X 12 Wing end face Y 13 Positioning pin hole 14 Positioning pin hole 15 Wing end face A 16 Wing end face B

Claims (6)

[Claims] In an impeller of a double suction type front blade multi-blade centrifugal blower comprising a pair of end rings, a plurality of blades, and a center disk, the blades are made of a metal blade mounting portion and the blade mounting portion. And a wing portion made of synthetic resin that is covered and fixed to the wing portion, and the wing mounting portion has through holes at both ends and an intermediate portion between the both ends where the synthetic resin is not covered, and the through holes at both ends. A blade structure having an opening between the intermediate through hole and a synthetic resin. 2. An impeller of a single-suction type front blade multi-blade centrifugal blower comprising an end ring, a plurality of blades, and a disk, wherein the blade is provided to cover a metal blade mounting portion and the blade mounting portion. The wing mounting portion has a through hole at both ends of which the resin is not covered, and an opening through which the synthetic resin is covered between the both end through holes. Have, the structure of the blade. 3. The blade structure according to claim 1, wherein an end of the wing mounting portion covered with a plastic material is bent. 4. The wing mounting portion according to claim 1, wherein the auxiliary positioning hole has an auxiliary positioning hole, and one side of the auxiliary positioning hole is covered with resin, and the other side is not covered with resin. The structure of the blade. 5. An auxiliary positioning hole is provided in a wing mounting portion, and a resin injection pressure is supported by an auxiliary positioning pin with a flange provided in an injection molding die to prevent deformation of the wing mounting portion and movement in the die. The blade manufacturing method according to any one of claims 1, 2, 3, and 4, wherein: 6. A wing portion resin for fixing a temperature of a wing mounting portion to a plurality of wing mounting portions in an injection molding step of covering and fixing a non-metal wing portion to a metal wing mounting portion. 6. The method for producing a blade according to claim 1, further comprising a step of preliminarily heating to approximately the same temperature as the temperature of the blade.