JPS5819357Y2 - Blower - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a blower that reduces the stress applied to the blades of the impeller.

FIGS. 1 and 2 show the main parts of a conventionally known type of blower, taking a single-suction type as an example.

In the figure, 1 is a disc-shaped main plate, 2 is a plurality of blades fixed to the peripheral edge of the main plate 1 by welding, etc., and 3 is an annular side plate facing the main plate 1 and fixed to the blade 2 by welding etc. , 4 is a rotating shaft, which is connected to the main plate 1 at a flange 4a by a rivet 5, and is rotationally driven by another prime mover.

Next, the operation of this blower will be explained.

When the rotating shaft 4 connected to the impeller 20 consisting of the main plate 1, blades 2 and side plates 3 is rotated, gas flows in from the opening on the inner circumferential side of the side plate 3 as shown by arrow A due to the rotation of the blades 2, and the blades 2 At the same time, the main plate 1 and the side plates 3 are displaced in the radial direction due to their own centrifugal force and the centrifugal force of the blades 2.

In general, the side plate 3 of the impeller 20 is an annular disk with a hollow inner circumference, whereas the main plate 1 is solid rather than hollow on the inner circumference. The rigidity is small;
The main plate 1 has high rigidity in the radial direction.

The above-described radial displacement amount is opposite to the radial rigidity, with the main plate 1 having a small radial displacement amount and the side plate 3 having a large displacement amount.

FIG. 10 is a diagram of the main part showing the amount of displacement of the impeller 20 shown in FIG. It shows a displaced state, and when rotating, the main plate is 1e and the blade is 2.
e, the side plate extends in the radial direction due to centrifugal force as shown in 3e.

As shown in the figure, the displacement of the impeller 20 is
is small like Dl, and the side plate 3 with low rigidity is large like D2. Therefore, the difference in displacement D2D1 between the side plate 3 and the main plate 1 is quite large, and the main plate tries to follow this difference in displacement D2 - DI. A large stress is generated in the blade 2.

If the stress generated in the blade 2 is large, the blade 2 may be cracked or deformed, or the blade 2 and the main plate 1 or side plate 3 may be damaged.
This is extremely dangerous as cracks may occur in the fixing part due to welding or the like, leading to damage to the impeller 20.

This idea was made with the aim of solving the above-mentioned drawbacks, and by removing a part of the main plate of the impeller, the radial rigidity of the main plate was brought close to that of the side plates. The radial displacement amount of the blade is brought closer to that of the side plate to reduce the difference in the radial displacement amount between the two, thereby reducing the stress applied to the blade. Since the structure is configured to prevent the deformation and damage of the impeller, the present invention provides a blower that can prevent deformation and damage of the impeller without reducing the efficiency of the blower due to ventilation from the cut portion.

An embodiment of this invention will be described below with reference to FIGS. 3 and 4.

In the figure, 1a is a cutout part provided in a part of the main plate 1,
Here, there are four through holes.

The fixed part of the main plate 1 with the blade 2 and the joint part with the flange 4a are bridged and fixed by the spokes 1b, and the spokes 1b
A through hole (Lla) is provided between the spoke 1b and the spoke 1b.

Reference numeral 6 denotes a closing plate provided as a means for preventing ventilation from the cut portion formed by the through hole 1a, and is connected to the main plate 1 with a rivet 7 to close the through hole 1a.

As mentioned above, since the main plate 1 has a plurality of through holes 1a, the rigidity of the main plate 1 is considerably lower than that without the through holes 1a, and the rigidity is close to that of the annular side plate 3. As a result, the radial displacement amount D1 of the main plate 1 when the impeller 20 rotates in FIG. 10 increases to a value close to the displacement amount D2 of the side plate 3, and the relative displacement amount D2-DI between the two also decreases. Therefore, the stress generated in the blade 2 can be reduced.

Further, gas passes through the through hole 1a made in the main plate 1 as shown by arrow B in FIG.
At that time, the gas collides with the spokes 1b of the main plate 1 and impedes the rotation of the impeller 20, increasing the power consumed by the impeller 20 and reducing efficiency. If you close it, the above problem will disappear.

This cover plate 6 can be divided into a plurality of pieces, and may be connected to the main plate 1 by bolts, welding, or the like.

Also, instead of attaching the cover plate 6 to the surface of the main plate 1 on the rotating shaft 4 side, it may be attached to the opposite surface on the blade 2 side.
In this case, when air is blown as indicated by arrow A in FIG. 3, vortices and the like caused by the recessed portion of the through hole 1a are not generated, and efficiency is not lowered.

Note that since the cover plate 6 can generally be made thinner than the main plate 1, the inertia of the impeller 20 is smaller than that of the conventional one, reducing the power of the prime mover and increasing the coordination in terms of blower control.

In addition, in order to prevent ventilation of the through hole 1a of the main plate 1, the fifth
The closing member 8 may be attached to the stationary part 9 as shown in FIG.

It is advantageous for the gap between the closing member 8 and the main plate 1 to be as narrow as possible to the extent that they do not come into contact with each other in terms of preventing ventilation.

Note that the stationary part 9 here is a bearing 10 that supports the rotating shaft 4.
Although the bearing box holds the bearing box, the closing member 8 may be attached to other stationary parts.

The structure shown in Fig. 5 or 6 has a slight amount of gas passing through the through hole 1a as shown by arrow C, so it is slightly more efficient than the structure shown in Fig. 3 in terms of preventing ventilation in the through hole 1a. However, since the blocking member is not connected to the rotating part, the strength of the blocking member 8 is not a problem, and the rigidity of the main plate 1 is not increased.

7 and 8 show another embodiment of this invention, in which a part of the main plate 1 is made thin 1C to reduce the rigidity of the main plate 1. An annular thin plate 1C is arranged between the fixed part with the blade 2 and the joint part with the flange 4a, and each is fixed by welding or the like.

However, the shape of the thin part 1C does not have to be annular, and the part where it is arranged does not have to be in the above-mentioned position, but may be any part of the main plate 1.

In addition, in order to increase the strength of the thin part 1C, a fourth
Spokes 1b as shown in the figure may be provided at several locations.

Figure 9 shows a part of the main plate 1 with a thin wall 1C, similar to the above-mentioned Figure 7.
As shown in this example, the impeller 20 can be integrally cast or made of synthetic resin or the like.

Further, the thin portion 1C may be formed by cutting the main plate 1.

Note that FIG. 9 shows an example of a double-suction type impeller 20 having blades 2 on both sides of the main plate 1. In such a case, the side plates 3 do not need to be provided on both sides and may be provided only on one side.

In the above embodiment, the side plate 3 is disk-shaped and the blade 2 is rectangular, but the side plate 3 may be tapered and the blade 2 may be trapezoidal.

As described above, this idea involves cutting out a part of the main plate of the impeller, reducing the radial stiffness of the main plate through this cut, and reducing the stiffness of the main plate by increasing the radial stiffness of the annular side plate, which is less rigid than the main plate. The radial displacement amount of the main plate during rotation is brought close to the radial displacement amount of the side plate to reduce the difference in the radial displacement amount between the two. Since we have provided a means to prevent ventilation from the cut-out portion of the blade, it is possible to reduce the stress on the blades fixed to the main plate and side plate without reducing the efficiency of the blower, thereby preventing deformation of the blades, etc. Damage can be prevented.

[Brief explanation of the drawing]

1 and 2 are diagrams showing the main parts of a conventional blower, with FIG. 1 being a sectional view seen from the side, and FIG. 2 being a plan view thereof. FIGS. 3 and 4 are views showing essential parts of a blower according to an embodiment of this invention, with FIG. 3 being a sectional view and FIG. 4 being a plan view. 5 to 7 and 9 are sectional views of other embodiments of this invention, and FIG. 8 is a plan view of FIG. 7. FIG. 10 is a diagram showing the radial displacement of a conventional impeller during rotation. In the figure, 1 is the main plate, 1a is the cutout of the main plate, 1b is the spoke, 1C is the thin part of the main plate, 2 is the blade, 3 is the side plate, 4
is a rotating shaft, 6 is a cover plate, 8 is a cover member, 9 is a stationary part, and 20 is an impeller. Note that the same reference numerals in the figures indicate the same or equivalent parts.

Claims (1)

[Scope of utility model registration request] A main plate coupled to a rotationally driven rotating shaft, a plurality of blades having one end fixed to the peripheral edge of the main plate, and an annular side plate fixed to the other end of these blades and facing the main plate. The blower is characterized in that the main plate is provided with a cut-out portion for removing a difference in rigidity in the radial direction of the side plates, and a means for preventing ventilation from the cut-out portion is provided on or near the main plate. .