JPS60145496A - Centrifugal blower - Google Patents

Abstract

PURPOSE:To balance pressure by varying each diameter on the both sides of a nozzle installed onto the side plate of a casing, when the interval between the edge surface of the motor and the edge surface of the casing is smaller than the outside diameter of a vane wheel, in a suction type centrifugal blower. CONSTITUTION:When the interval L between the edge surface 3 of a casing 1 which covers the both multiblade vane wheels 6a and 6b for suction and the edge surface of a motor 8 is less than the outside diameter of the vane wheel 6, the inside diameter of a nozzle 5 installed onto the side plate of the casing 1 is set so that the relation d1<d2 is established, in which the inside diameter on the motor side is d2 and that on the other side is d1, and the resistance for the suction into the vane wheel 6 is made equal, and the revolution of the vane wheel 6 is stabilized. Therefore, as for the air inhaled into the vane wheel, the resistance on the suction side is balanced by setting larger the diameter of the nozzle 5 positioned on the side where the motor is installed, and the flow of air is stabilized, and the vibration of the vane wheel 6 due to the difference of resistance on the suction side is eliminated, and the increase of noise can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to improving the blowing performance of a double-suction type centrifugal blower used in air conditioners and the like and reducing vibration noise during operation.

Conventional structure and its problems Conventionally, a double suction type centrifugal blower has a dual suction type centrifugal blower that drives a double suction multiblade impeller (hereinafter simply referred to as an impeller). The impeller is installed near the casing, but in order to simplify the structure of the double-suction type centrifugal blower, the impeller is directly fixed to the motor shaft.

However, in such cases, it is necessary to support the weight of the impeller in a cantilevered manner only by the motor shaft, and for this reason, the length of the shaft must be designed to be as short as possible in terms of strength and cost. No. As a result, the motor is installed close to one side of the nozzle provided on both side plates of the casing of a double-suction centrifugal blower, which causes an imbalance in the resistance when drawing air, resulting in poor air blowing performance. It had problems such as instability, vibration, and increased noise.

OBJECT OF THE INVENTION The present invention is intended to solve these problems, and is intended to solve the problem when the impeller drive motor is installed very close to the casing side plate of a double-suction type centrifugal blower, or when a part of the motor is attached to the impeller. Even if it gets inside the car, it will ensure stable air blowing performance, making it easy to use while driving.

The purpose is to prevent an increase in vibration and noise.

In order to achieve the configuration and object of the invention, the diameters of the nozzles provided on both sides of the casing of a double-suction type centrifugal blower are changed depending on the mounting position of the motor.

With this configuration, when a double-suction type centrifugal blower is operated, air is drawn into the impeller through the nozzles provided on both sides of the casing by setting the diameter of the nozzle on the motor mounting side to a large diameter. The resistance on the suction side is balanced and the flow becomes stable, and furthermore, the vibration of the impeller due to the difference in resistance on the suction side is eliminated, and an increase in noise can also be suppressed.

DESCRIPTION OF EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

In Fig. 1, 1 is the casing of a double-included centrifugal blower;
2 is the double suction type centrifugal blower casing JP-A-Sho GO-1
45496 (2) Side plate A of 1 opposite to the side where the motor is attached,
3 is the side plate B of the double-suction type centrifugal blower casing 1 on which the motor is attached, 4 is the nozzle part A provided on the side plate A2, 6 is the nozzle part B provided on the side plate 3, and e is the side on which the motor is attached. A multi-blade suction impeller (hereinafter referred to as an impeller) 7 is a discharge port, 8 is a motor for driving the impeller 6, and 9 is a shaft of the motor 8 to which the impeller 6 is fixed. Further, FIG. 2 shows a sectional view taken along the line A--A in FIG. 1. FIG. 3 shows an enlarged view of the nozzle portions A4, Bes and the impeller 6. In Figures 1 to 3, L is side plate B
3 and the end surface of the motor 8, D is the outer diameter of the impeller 6, dl is the inner diameter of the nozzle A4, and d2 is the inner diameter of the nozzle B5.

Air flow will be explained using FIGS. 1 to 3.

When the impeller 6 is rotated by the drive of the motor 8, air flows through the nozzles A4, . B
6 and is sucked into the impeller 6, given energy within the casing 1, and sent out from the discharge lower. In this case, if the distance between the side plate B3 and the motor 8 is narrow, the flow of air will be obstructed by the motor 8, so the amount of air passing through the nozzle B6 and sucked into the impeller 6 will be It is small compared to the amount of air that passes through A4 and is sucked into the impeller 6. This difference in flowing air causes unstable rotation of the impeller 6, and further causes vibration of the impeller 6 in the axial direction due to the pressure difference. Inner diameter d1. Inner diameter d2 of nozzle B5
is set as dl<d2, and a structure is used in which the rotation of the impeller 6 is stabilized by making the resistance until it is sucked into the impeller 6 the same.

Effects of the Invention As is clear from the above embodiments, the diameter of the nozzle provided on the suction side is varied depending on the resistance on the two air suction sides of the double suction centrifugal blower of the present invention. You can secure the blower.

[Brief explanation of drawings]

Fig. 1 is a front view of a double-suction type centrifugal blower which is an embodiment of the present invention, Fig. 2 is a sectional view taken along line A-A in Fig. 1, and Fig. 3 is an enlarged sectional view of the main part of Fig. 1. It is. 1...Casing, 2...Side plate, 4,
6...Nozzle, 6...Double suction multi-blade impeller, 7...Discharge port, 8...Motor,
9... Axis.

Claims (1)

[Claims] an end face of a motor for driving both suction multi-blade impellers;
If the minimum distance between the end face of the casing side plate on the side facing the motor is smaller than the outer diameter dimension of both suction multi-blade impellers, the diameter of the nozzle provided on the casing side plate on the side facing the motor A centrifugal blower with a small diameter nozzle installed in the casing on the side opposite to the motor.