JP7519239B2 - Centrifugal Blower - Google Patents

Description

The present invention relates to a centrifugal blower that houses a resin impeller with multiple blades integrally formed inside a casing and blows air by rotating the impeller inside the casing using a motor.

A centrifugal blower is known that blows air by rotating an impeller having multiple blades inside a casing. The multiple blades are erected from the circumference of a rotating disk, and the upper ends of the multiple blades are connected to a ring-shaped top plate. A motor shaft is connected to the center of the rotating disk, and the impeller can be rotated inside the casing by rotating the motor. As a result, centrifugal force acts on the air present between the blades, generating an outward air flow, and the pressure generated between the outside of the impeller and the inside of the casing by this air flow causes air to flow out from a blower port formed on the side of the casing. In addition, as a result of this, the inside of the impeller becomes negative pressure, so air flows into the inside of the impeller from an air intake port formed in the center of the ring-shaped top plate.

Such centrifugal blowers blow air by rotating an impeller at high speed, which generates vibration and noise as it rotates. To suppress this vibration and noise, the impeller must be manufactured with a sufficiently high degree of precision so that imbalance with respect to the rotating shaft is as small as possible. Furthermore, when assembling the impeller to the motor, it is necessary to align the impeller's rotating shaft with the motor's rotating shaft as closely as possible, but some degree of error during assembly is unavoidable.

Therefore, a technology has been proposed in which, with the impeller attached to the motor, a balance weight is attached to the impeller through an air intake opening in the center of the top plate, thereby adjusting the balance of the motor and impeller as a whole (Patent Document 1).

JP 2010-031664 A

However, with the above-mentioned proposed technology, if the air intake of the impeller mounted on the centrifugal blower is small in diameter, it is difficult to attach the balance weight to the blade plate, resulting in poor workability.

This invention was made to solve the above-mentioned problems with the conventional technology, and aims to provide a centrifugal blower that can be easily balanced even when the impeller's air intake is small in diameter.

In order to solve the above-mentioned problems, the centrifugal blower of the present invention adopts the following configuration.
A centrifugal blower includes a resin impeller having a plurality of blades integrally formed therewithin, the resin impeller being housed in a casing, and the impeller is rotated by a motor to blow air,
The impeller comprises:
a rotating disk having the plurality of blades arranged upright on a circumference thereof;
a connection portion formed at the center of the rotating disk and to which a rotating shaft of the motor is connected;
and a ring-shaped top plate formed integrally with the upper ends of the plurality of slats,
A plurality of through holes for attaching balance weights are formed in the top plate at equal intervals at positions equidistant from the center of the top plate ,
The through hole of the top plate is formed in a position where the upper end of the slat is integrally formed, straddling the slat,
The balance weight has a pair of legs that are inserted into both sides of the slat through the through hole.
It is characterized by:

In the centrifugal blower of the present invention, a resin impeller with a plurality of blades integrally formed therewith is housed in a casing, and the impeller is connected to a rotating shaft of a motor. The impeller is rotated in the casing to blow air. The impeller's plurality of blades stand upright from a rotating disk, and the upper ends of the blades are connected to a ring-shaped top plate. Furthermore, the top plate is formed with a plurality of through holes at equal intervals at positions equidistant from the center of the top plate, to which balance weights are attached. These through holes are formed in positions where the upper ends of the blades are integrally formed with the top plate, straddling the blades, and the balance weight is provided with a pair of legs that are inserted into both sides of the blades through the through holes.

In this way, with the impeller attached to the motor, the balance of the impeller and the motor as a whole can be adjusted by attaching a balance weight to the through hole formed in the top plate. Also, since the through hole is formed in the top plate, even if the impeller has a small diameter air intake formed in the center of the top plate, the balance weight can be easily attached, making it possible to easily adjust the balance.

In addition, since the through hole is provided in the top plate, the moment generated by attaching the balance weight to the through hole is large. Therefore, it is possible to adjust the balance using a lightweight balance weight, and it is possible to prevent the weight of the centrifugal blower from increasing. Furthermore, since the balance weight can be made small, the balance weight does not become an air resistance when the impeller is rotated, and does not increase the torque required for rotation. In addition, when the balance weight is attached to the through hole, the legs of the balance weight are inserted on both sides of the blade plate. Therefore, even if the balance weight tries to tilt, the legs inserted on the left and right sides of the blade plate come into contact with the blade plate, making it difficult for the balance weight to tilt, and the posture of the balance weight when attached to the through hole can be stabilized. Furthermore, since the balance weight is attached by inserting the legs into the through hole from above, the balance weight will not come off due to centrifugal force even when the impeller rotates.

In addition, in the centrifugal blower of the present invention described above, the balance weight may be formed from an elastic material, and when a pair of legs of the balance weight are inserted through the through hole, the pair of legs may come into contact with both sides of the blade plate.

In this way, when the balance weight is attached to the through hole, the pair of legs will use their elasticity to clamp the slats from both sides, making it possible to attach the balance weight in a firmly fixed state.

In addition, in the centrifugal blower of the present invention described above, a retaining portion may be formed by folding back the tip of at least one of the pair of legs.

The anti-slip portion is formed by folding back the tip of the leg, so when the leg is inserted into the through-hole, the anti-slip portion elastically deforms and can pass through the through-hole, so the balance weight can be easily attached to the through-hole even with the anti-slip portion. However, when an attempt is made to remove the inserted leg, the anti-slip portion cannot pass through the through-hole (unless it is intentionally elastically deformed), so the leg will not come out. For this reason, by providing the anti-slip portion on the leg, it is possible to prevent the balance weight attached to the through-hole from coming out on its own. Also, if the anti-slip portion is pressed down to elastically deform it so that it can pass through the through-hole, it is possible to remove the balance weight attached to the through-hole.

1 is an explanatory diagram showing a general structure of a centrifugal blower 1 according to an embodiment of the present invention; 1 is an exploded view showing a structure for attaching the impeller 10 of the centrifugal blower 1 of the present embodiment to the motor 4. FIG. 2 is an explanatory diagram showing an enlarged view of a portion where a through hole 16 is formed in a top plate 13 of the impeller 10 of the present embodiment. FIG. 2 is a cross-sectional view showing a state in which a balance weight 20 is attached to a through hole 16 of the impeller 10 of the present embodiment. FIG. 10 is an explanatory diagram of a balance weight 20 according to a first modified example. FIG. 13 is an explanatory diagram of a balance weight 20 according to a second modified example. FIG.

Figure 1 is an explanatory diagram showing the general structure of the centrifugal blower 1 of this embodiment. Figure 1(a) shows the external shape of the centrifugal blower 1, and Figure 1(b) shows the internal structure of the centrifugal blower 1. As shown in the figure, the centrifugal blower 1 of this embodiment has a structure in which an impeller 10 is housed inside a casing 2.

The casing 2 is formed by combining sheet metal members, and the side of the casing 2 has an air outlet 2b for blowing out air, and the center of the top surface of the casing 2 has an air inlet 2a for sucking in air. The impeller 10 is a short cylindrical member with an external shape, and is rotatably attached to a disk-shaped mounting plate 3 with a larger diameter than the impeller 10. When the mounting plate 3 is screwed to the casing 2 from below the casing 2 using the mounting screws 3s with the impeller 10 attached to the mounting plate 3, the impeller 10 is housed in the casing 2. As described later, the impeller 10 can be rotated by the motor 4 (see FIG. 2). When the impeller 10 is rotated inside the casing 2, air is sucked into the casing 2 through the air inlet 2a and blown out through the air outlet 2b.

Figure 2 is an exploded view showing the structure for mounting the impeller 10 of this embodiment to the motor 4. As shown in the figure, the motor 4 is formed in a cylindrical shape, with a rotating shaft 4a protruding from the same axis as the cylindrical shape, and a disk-shaped flange portion 4b with a larger diameter than the motor 4 is formed on the end face on the side where the rotating shaft 4a protrudes. The flange portion 4b has three mounting holes 4c, and the motor 4 is attached to the mounting plate 3 through the three mounting holes 4c using mounting screws 4s.

The mounting plate 3 is a ring-shaped member made of sheet metal, and the circular opening 3a at the center is formed with a smaller diameter than the flange portion 4b of the motor 4. Therefore, the motor 4 can be attached to the mounting plate 3 by closing the opening 3a with the flange portion 4b of the motor 4 and screwing it in place. When the motor 4 is attached to the mounting plate 3 in this manner, the rotating shaft 4a of the motor 4 protrudes from the center of the opening 3a. The outer diameter of the mounting plate 3 is also formed to be larger than the impeller 10.

The impeller 10 has multiple vanes 12 standing on the circumference of a rotating disk 11, and the upper ends of the multiple vanes 12 are integrally formed with a circular top plate 13. A short cylindrical inner wall 13a protrudes upward from the inner diameter side of the top plate 13, and an air intake 13b is formed inside the inner wall 13a. When the impeller 10 is housed in the casing 2 as shown in Figure 1, this air intake 13b faces the suction port 2a of the casing 2.

The blades 12 are not only erected from the circumference of the rotating disk 11, but also extend outward from the rotating disk 11. The lower ends of the extended blades 12 are integrally formed with a ring plate 14. The inner diameter of the ring plate 14 is set to a value larger than the outer diameter of the top plate 13, and the inner diameter of the top plate 13 is set to a value larger than the outer diameter of the rotating disk 11. Therefore, the impeller 10 is integrally formed by injection molding a resin material.

Furthermore, a disk-shaped connection part 15 protrudes from the center of the rotating disk 11, and an insertion hole 15a through which the rotating shaft 4a of the motor 4 is inserted penetrates the center of the rotating disk 11 and the connection part 15. A hexagonal recess 15b is formed on the upper surface of the connection part 15, and a hexagonal insulator 5 made of a vibration-damping material such as rubber is fitted into the recess 15b.

The insulator 5 also has a through hole 5b in the center through which the rotating shaft 4a of the motor 4 is inserted, and furthermore, a hexagonal recess 5a is formed on the top surface of the insulator 5. A hexagonal metal washer 6 is fitted into the recess 5a of the insulator 5. The washer 6 also has a through hole 6a in the center through which the rotating shaft 4a of the motor 4 is inserted.

When attaching the impeller 10 to the rotating shaft 4a of the motor 4, the rotating shaft 4a of the motor 4 is inserted into the insertion hole 15a of the impeller 10, the rotating shaft 4a protruding from the insertion hole 15a is inserted into the insertion hole 5b of the insulator 5, and then the insulator 5 is fitted into the recess 15b of the connection part 15. Next, the rotating shaft 4a protruding from the insertion hole 5b of the insulator 5 is inserted into the insertion hole 6a of the washer 6, and then the washer 6 is fitted into the recess 5a of the insulator 5. Finally, the nut 7 is attached to the rotating shaft 4a protruding from the insertion hole 6a of the washer 6. In this way, the impeller 10 can be attached to the rotating shaft 4a of the motor 4. As shown in the figure, the rotating shaft 4a of the motor 4 has a D-cut shape with a flat cut side, and the insertion hole 6a of the washer 6 also has a D-cut shape to match the rotating shaft 4a. As a result, the washer 6 is not pulled and rotated by the rotation of the nut 7, so the impeller 10 can be attached to the rotating shaft 4a without applying a twisting force to the insulator 5.

Here, the impeller 10 is formed with high dimensional accuracy by integral molding, so the imbalance around the central axis of the insertion hole 15a is sufficiently small. However, when attaching the impeller 10 to the rotating shaft 4a of the motor 4, it is difficult to perfectly align the central axis of the insertion hole 15a of the impeller 10 with the central axis of the rotating shaft 4a of the motor 4, and it is difficult to avoid some positional misalignment. And if the positional misalignment when attaching the impeller 10 to the rotating shaft 4a of the motor 4 becomes large, the imbalance around the rotating shaft 4a of the motor 4 becomes large, and large vibrations and noise are generated when the impeller 10 is rotated.

In this embodiment, the impeller 10 has a plurality of through holes 16 formed at equal intervals on the outer periphery of the top plate 13. Here, the outer periphery of the top plate 13 refers to the portion whose distance from the center of the top plate 13 is greater than the average distance between the inner periphery of the annular top plate 13 and the outer periphery of the top plate 13. By attaching a balance weight 20 (described later) to the through holes 16 formed in such a position, it becomes possible to adjust the balance around the rotating shaft 4a after the impeller 10 is attached to the rotating shaft 4a of the motor 4.

Figure 3 is an explanatory diagram showing an enlarged view of a portion of the top plate 13 of the impeller 10 where the through hole 16 is formed. In Figure 3, the through hole 16 is shown with diagonal lines. As shown in the figure, the through hole 16 has a rectangular shape and is formed through the top plate 13. Furthermore, the blade plate 12 is connected to the top plate 13 from below, and the through hole 16 is formed across the blade plate 12. Therefore, when the through hole 16 is viewed from above, it appears to be divided into two by the blade plate 12.

Figure 3 also shows the balance weight 20 that is attached to the through hole 16. The balance weight 20 is formed by bending a thin plate-shaped spring material near the center in the longitudinal direction, and has a pair of legs 20a that extend in approximately the same direction from both sides of the bent position. One of the pair of legs 20a has a tip that is folded back to form a stopper portion 20b. Note that while Figure 3 shows that the stopper portion 20b is formed on one of the pair of legs 20a, it may be formed on both legs 20a.

When attaching the balance weight 20 to the through hole 16, one leg 20a of the balance weight 20 is inserted into one side of the through hole 16 divided by the slats 12, and the other leg 20a is inserted into the other side of the through hole 16. When inserting these legs 20a into the through hole 16, the retaining portion 20b formed at the tip of the leg 20a abuts against the inner wall surface of the through hole 16 and deforms, allowing the leg 20a to be inserted. After the retaining portion 20b passes through the through hole 16, the deformed retaining portion 20b returns to its original shape. From that state, the balance weight 20 is inserted until it contacts the upper end of the slats 12, completing the attachment of the balance weight 20.

Figure 4 is a cross-sectional view of the balance weight 20 attached to the through hole 16 of the top plate 13. The cross-sectional position is the position indicated by A-A in Figure 3. As shown in the figure, when the balance weight 20 is attached to the through hole 16, a pair of legs 20a abuts on both sides of the blade plate 12, so that the balance weight 20 is stable. Since the balance weight 20 is inserted from above into the through hole 16 of the top plate 13 and attached, it is possible to prevent the balance weight 20 from coming off due to centrifugal force even when the impeller 10 is rotated at high speed. In addition, since the balance weight 20 is attached to the through hole 16 formed in the top plate 13, the attached balance weight 20 is housed in the through hole 16 and does not protrude from the top plate 13. Therefore, when the impeller 10 is rotated, the balance weight 20 does not become air resistance and the torque required for rotation does not increase.

In addition, the balance weight 20 is formed from a thin plate-shaped spring material, and when the balance weight 20 is attached, the pair of legs 20a are pressed against the slats 12 by the spring force. This makes it possible to more firmly stabilize the balance weight 20 attached to the through hole 16. Furthermore, one of the legs 20a has a tip that is folded back to form a retaining portion 20b, so the balance weight 20 attached to the through hole 16 will not fall out upwards. Nevertheless, if the retaining portion 20b is pressed from above with a flathead screwdriver or the like to deform it, the balance weight 20 attached to the through hole 16 can be easily removed.

In the centrifugal blower 1 of this embodiment, such a balance weight 20 can be attached to the through hole 16 formed in the top plate 13 of the impeller 10. Therefore, after the impeller 10 is attached to the rotating shaft 4a of the motor 4, the balance can be adjusted using the balance weight 20. As described above, the through hole 16 for attaching the balance weight 20 is formed in the top plate 13 of the impeller 10, so that the balance weight 20 can be easily attached even if the inner diameter of the air intake 13b formed on the inside of the top plate 13 becomes small. In addition, since the through hole 16 for attaching the balance weight 20 is formed on the outer periphery of the top plate 13, the distance from the rotating shaft 4a of the motor 4 to the balance weight 20 can be increased. Therefore, it is possible to adjust the balance using a small balance weight 20.

In the above embodiment, the balance weight 20 is attached stably to the through hole 16 by abutting the pair of legs 20a on the balance weight 20 on both sides of the slat 12. However, the balance weight 20 can be attached stably to the through hole 16 even if the pair of legs 20a do not necessarily have to abut on both sides of the slat 12. Such modified examples are briefly described below.

Figure 5 is an explanatory diagram of a first modified balance weight 20 in which a pair of legs 20a abut against the inner wall surfaces 16a on both sides of the through hole 16. Like the balance weight 20 of the above-mentioned embodiment, the balance weight 20 of the first modified balance weight is also formed by bending a thin plate-shaped spring material, but the pair of legs 20a of the balance weight 20 of the first modified balance weight are formed by bending both sides of the main body 20c. The length of the main body 20c is shorter than the distance between the inner wall surfaces 16a on both sides of the through hole 16, and furthermore, the distance between the pair of legs 20a becomes wider toward the tip.

The balance weight 20 of this first modified example is inserted into the through hole 16 with the tips of the pair of legs 20a deformed to bring them closer together, and then when the deforming force is released, the pair of legs 20a spread apart and come into contact with the inner wall surface 16a of the through hole 16. When the balance weight 20 is pushed into the through hole 16 in this state, the main body 20c of the balance weight 20 comes into contact with the upper end of the slat 12, and the balance weight 20 can be attached to the through hole 16 in a stable state as shown in Figure 5.

Figure 6 is an explanatory diagram of a second modified balance weight 20 in which a pair of legs 20a abut against the inner wall surfaces 16a on both sides of the through hole 16. The second modified balance weight 20 is also formed by bending a thin plate-shaped spring material, and includes a main body 20c and a pair of legs 20a formed by bending both sides of the main body 20c. However, in the second modified example, the length of the main body 20c is longer than the distance between the inner wall surfaces 16a on both sides of the through hole 16, and the pair of legs 20a formed on both sides of the main body 20c are formed in a shape that gradually narrows toward the tip and then widens again (i.e., an inwardly convex shape). In addition, the tips of the pair of legs 20a are folded back outward to form a slip-out prevention portion 20b.

In the balance weight 20 of the second modified example, the tips of the pair of legs 20a are deformed to approach each other, and when the deforming force is released after the tips of the legs 20a are inserted into the through hole 16, the pair of legs 20a spread out and come into contact with the inner wall surface 16a of the through hole 16. As described above, the pair of legs 20a are formed in an inwardly convex shape, so that the pair of legs 20a spread out, positioning the balance weight 20 relative to the through hole 16. In addition, the main body 20c of the balance weight 20 is formed longer than the inner wall surfaces 16a on both sides of the through hole 16, so that even if a force acts to push the balance weight 20 into the through hole 16, the main body 20c interferes with the through hole 16 and the balance weight 20 is not pushed in any further. Furthermore, the tips of the pair of legs 20a are formed with anti-pullout portions 20b, so the balance weight 20 inserted into the through hole 16 will not slip out upward.

The balance weight 20 of the second modified example shown in FIG. 6 can be attached to the through hole 16 even without the slats 12. Therefore, the position where the through hole 16 is formed can be on the outer periphery of the top plate 13, and does not necessarily have to be the position where the slats 12 are connected. This makes it possible to increase the degree of freedom in the position where the through hole 16 is provided on the top plate 13.

The centrifugal blower 1 of this embodiment and various modified examples has been described above, but the present invention is not limited to the above embodiment and various modified examples, and can be implemented in various forms without departing from the spirit of the invention.

REFERENCE SIGNS LIST 1... centrifugal blower, 2... casing, 2a... suction port, 2b... blower port,
3...Mounting plate; 3a...Opening; 3s...Mounting screw; 4...Motor;
4a...rotating shaft; 4b...flange portion; 4c...mounting hole; 4s...mounting screw;
5... insulator; 5a... recess; 5b... insertion hole; 6... washer;
6a... insertion hole; 7... nut; 10... impeller; 11... rotating disk;
12... vane plate, 13... top plate, 13a... inner wall, 13b... air intake,
14... ring plate; 15... connection portion; 15a... insertion hole; 15b... recessed portion;
16... through hole; 16a... inner wall surface; 20... balance weight;
20a... Leg portion, 20b... Retaining portion, 20c... Main body portion.

Claims (3)

A centrifugal blower includes a resin impeller having a plurality of blades integrally formed therewithin, the resin impeller being housed in a casing, and the impeller is rotated by a motor to blow air,
The impeller comprises:
a rotating disk having the plurality of blades arranged upright on a circumference thereof;
a connection portion formed at the center of the rotating disk and to which a rotating shaft of the motor is connected;
and a ring-shaped top plate formed integrally with the upper ends of the plurality of slats,
A plurality of through holes for attaching balance weights are formed in the top plate at equal intervals at positions equidistant from the center of the top plate ,
The through hole of the top plate is formed in a position where the upper end of the slat is integrally formed, straddling the slat,
The balance weight has a pair of legs that are inserted into both sides of the slat through the through hole.
A centrifugal blower characterized by the above. The centrifugal blower according to claim 1,
The balance weight is formed of an elastic member,
When the pair of legs are inserted through the through hole, they come into contact with both sides of the slat.
A centrifugal blower characterized by the above. The centrifugal blower according to claim 2,
At least one of the pair of legs has a tip that is folded back to form a retaining portion.
A centrifugal blower characterized by the above.

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