JPH0765593B2 - Axial blower - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention provides an axial blower in which an electric motor directly connected to an impeller is installed in a casing surrounding the impeller, and a fluid flows in and out of the impeller in an axial direction. , For example, relates to an axial blower used for ventilation of an automobile tunnel.

[Conventional technology]

As an axial blower, there is known one in which an impeller provided with blade rows is directly connected to a rotor shaft of an electric motor and the electric motor is housed in a casing surrounding the impeller. FIG. 2 shows a conventional axial-flow blower of this type. In the figure, reference numeral 1 denotes an impeller in which a blade row 2 is attached to a boss 3, which is directly connected to a rotor shaft of an electric motor 4.

The electric motor 4 is housed in a hub 5 adjacent to the boss 3 of the impeller 1 and fixed to the hub 5 via a mount 6. Hub 5
Has a cylindrical shape that is concentric with the axial center of the impeller 1, and subsequently has a conical portion 7 that is also concentric. Reference numeral 8 is a guide cone that guides the fluid to the blade row of the impeller 1.

The casing 10 is a cylinder that is separated from the outer peripheral tip of the blade row 2 of the impeller 1 and is concentric with the axial center of the impeller 1.
A plurality of stays 11 mounted on the support 10 supports the hub 5 having the conical portion 7. The stay 11 also serves as a guide vane for removing the swirling flow provided by the blade row 2. A flow passage 13 for the fluid flowing out from the blade row 2 of the impeller 1 is formed between the casing 10 and the hub 5, and subsequently, a diffuser 14 is formed which is a flow passage that widens from the conical portion 7. There is.

With such a structure, the impeller 1 is energized by energizing the electric motor 5.
When is rotated, the fluid is sucked from the inlet 15 of the casing 10, the fluid whose pressure is increased by passing through the blade row 2 of the impeller 1 passes through the stay 11, the swirling flow is removed, and the fluid is passed through the flow path 13 to the diff user 14. After flowing, the pressure is restored and the air is sent from the casing 10 to the outside.

[Problems to be Solved by the Invention]

In the axial blower, the blade row 2 of the impeller 1 is a deceleration blade row, so the fluid passing through the blade row 2 is decelerated, and the pressure increases along the flow direction, so that along the hub 5 and the casing 10. The boundary layer becomes thicker. At this time, since the electric motor 4 directly connected to the impeller 1 is housed in the hub 5, the size of the hub 5, in particular the length, is necessarily increased. Therefore, the fluid flowing out of the blade row 2 flows along the long-sized hub 5, so that the boundary layer grows and flows into the diff user 14 in a state where the thickness of the boundary layer becomes large, so that the fluid has a high pressure recovery rate. However, there is a drawback that the efficiency of the blower becomes low.

It is an object of the present invention to provide an axial blower with high efficiency by reducing the thickness of the inlet boundary layer of the flow entering the diff user to obtain a high pressure recovery rate.

[Means for Solving the Problems]

In order to achieve the above object, according to the present invention, an impeller provided with a blade row, a cylindrical casing that is concentric with the impeller away from the outer periphery of the impeller, and is arranged in this casing. In an axial blower in which a fluid flows in from an impeller side, the electric motor is directly connected to the impeller, the electric motor being supported by a plurality of stays attached to an inner surface of the casing, and a cylindrical portion concentric with the impeller. A stator frame having a conical portion continuing from this is provided, and the conical portion forms a diffuser in a flow path downstream from the stay.

[Action]

A flow path for fluid flowing out from the blade row is formed between the stator frame and the casing of the electric motor, and a flow path downstream from the stay forms a Diffuser by a conical stator frame. Therefore, the impeller rotates due to the energization of the electric motor and the fluid sucked into the casing flows with increased pressure from the blade row that is the reduction blade row, and the fluid from which the swirling flow has been removed by the stay immediately flows into the diff user. The thickness of the inlet boundary layer of the flow entering the diff user is reduced, and thus a high pressure recovery force is obtained.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a sectional view of an axial flow fan according to an embodiment of the present invention. In FIG. 1, the same parts as those in the conventional example of FIG. 2 are designated by the same reference numerals, and the description thereof will be omitted. 1 differs from the conventional one in that the stator frame 20 of the electric motor 4 is formed of a cylindrical portion 21 forming a hub supported by a stay 11 attached to the inner surface of the casing 10, and a conical portion 22 following the cylindrical portion 21. That is what I configured. As a result, a flow path of the fluid flowing out from the blade row 2 is formed between the stator frame 20 and the casing 10, and the conical portion 22 forms a diffuser 14 in the flow path downstream of the stay 11.

With such a structure, when the impeller 1 is rotated by energization of the electric motor 4, the fluid sucked into the casing 10 flows from the blade row 2 with increased pressure and flows through the stay 11 to remove the swirling flow. Immediately after it flows into the differential user 14 formed by the conical portion 22 of the stator frame 20, the thickness of the inlet boundary layer of the flow entering the differential user 14 becomes thin, and a high pressure recovery force is obtained.

〔The invention's effect〕

As apparent from the above description, according to the present invention, as a result of adopting the above configuration, the fluid flowing out of the blade row of the impeller is formed in the conical portion of the stator frame immediately after passing through the stay. Since the flow enters the diff user, the thickness of the inlet boundary layer of the flow flowing into the diff user is reduced, a high pressure recovery rate is obtained, and the efficiency of the axial blower is improved. Moreover, since the electric motor is not housed in the hub as in the conventional case, the outer diameter of the electric motor can be increased, and accordingly, the length dimension of the electric motor can be reduced, which makes the axial blower compact. be able to.

[Brief description of drawings]

FIG. 1 is a sectional view of an axial blower according to an embodiment of the present invention, and FIG. 2 is a sectional view of a conventional axial blower. 1: Impeller, 2: Blade row, 4: Electric motor, 11: Stay, 14: Diff user, 20: Stator frame, 21: Cylindrical part, 22: Conical part.

Claims (1)

[Claims] 1. An impeller having a row of blades, and a cylindrical casing separated from the outer circumference of the impeller and concentrically surrounding the impeller.
In an axial blower, which is arranged in the casing and is directly connected to the impeller, in which fluid flows from the impeller side, the electric motor is supported by a plurality of stays attached to the inner surface of the casing. An axial-flow blower comprising a stator frame including a cylindrical portion concentric with a vehicle and a conical portion continuing from the cylindrical portion, and the conical portion forms a diffuser in a flow passage downstream of the stay.