JPS6234000Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to an improvement of an electric pump that is installed by being immersed in fuel, etc., in an aircraft fuel tank, and particularly relates to an electric pump that improves pump efficiency (flow rate vs. discharge pressure characteristics). .

FIG. 1 is a partial sectional side view of a conventional electric pump of this type.

In the figure, 1 is a housing of an electric pump whose interior is divided into a seal chamber 2 and a pump chamber 3, and 4 is a casing that houses an electric motor (not shown) in a motor chamber 5, which is fixed to the housing 1. . 6
A shaft is rotationally driven by an electric motor, and extends through the seal chamber 2 and projects into the pump chamber 3. 7 is an impeller, 8 is a key, and 9 is a nut. The impeller 7 is fixed to the tip of the shaft 6 with the key 8 and the nut 9, and rotates integrally with the shaft 6. Reference numeral 10 denotes an oil seal installed between the shaft 6 and the partition wall 11 of the seal chamber 2, and maintains a sealed state between the seal chamber 2 and the motor chamber 5. A snap spring 12 is attached to a groove of the housing 1 to prevent the oil seal 10 from coming off in the axial direction. 13 is a fitting, and 14 is several screws. The fitting 13 is fixed to the housing 1 by the several screws 14, and an O-ring 15 for sealing is attached to the fitting part with the housing 1. 16 is a discharge port provided in the fitting 13. 17 is a tank, the housing 1 is fixed to the tank 17 by several screws 18, and a sealing O-ring 19 is attached to the fitting part with the tank 17. 20
is an opening of the housing 1, and 21 is a suction port of the pump. 22 is a space formed by the rear surface of the impeller 7 and the fitting 13. A lead wire 23 supplies electrical input from a power source outside the pump to a motor (not shown) in the motor chamber 5 through the through hole 24 of the housing 1. 25 is the fuel in the tank 17.

Next, the operation of the conventional device shown in FIG. 1 will be explained.

First, when the electric motor in the motor chamber 5 is driven by an external power input, the impeller 7 and the shaft 6 are driven.
rotates in a predetermined direction. Due to this rotation of the impeller 7, the fuel 25 in the tank 17 is sucked through the opening 20 of the housing 1, from the suction port 21 of the pump, and is sent to the pump chamber 3. The fuel 25 thus delivered is forcedly delivered toward the discharge port 16 through a space 22 formed between the back surface of the impeller 7 and the fitting 13. At this time, the oil seal 10 attached to the partition wall 11 of the seal chamber 2 of the housing 1 maintains a sealed state inside and outside, and the fuel 25 in the seal chamber 2 does not enter the motor chamber 5.

Here, in a normal centrifugal pump, a spiral chamber is provided in the radial direction near the outlet of the impeller in the pump chamber, and both pressure and velocity energy are given to the fuel pumped by the rotation of the impeller. While the fuel passes through the spiral chamber, its velocity energy is efficiently converted into pressure energy and the fuel is pumped toward the discharge port.

However, according to the conventional pump shown in FIG. 1, the housing 1 has a through hole 24 through which the lead wire 23 is passed, and there is a restriction that the pump chamber 3 cannot be enlarged. Therefore, the pump chamber 3 is not provided with a spiral chamber in the radial direction, and the fuel 25 sent out by the rotation of the impeller 7 passes through the pump chamber 3 and is immediately formed between the back surface of the impeller 7 and the fitting 13. The discharge port 16 is
It will be forced towards. For this reason, the velocity energy obtained by the rotation of the impeller 7 cannot be efficiently converted into pressure energy, resulting in a disadvantage that the efficiency of the pump deteriorates and the flow rate vs. discharge pressure characteristic deteriorates significantly.

[Purpose of invention]

The present invention has been developed in consideration of the above points, and is applicable to electric pumps that are limited by the size of the pump chamber and cannot be provided with a spiral chamber for guiding the fluid pumped by the impeller in a radial direction. Another object of the present invention is to provide an electric pump that can efficiently convert velocity energy obtained by rotation of an impeller into pressure energy and improve efficiency.

[Structure of the invention] In order to achieve the above-mentioned object, the present invention includes a shaft that is rotationally driven by an electric motor, and a shaft that is fixed to a portion of the housing at one end of the shaft that protrudes into the pump chamber, and that rotates integrally with the shaft. an impeller that is sealed in the housing, a part of which constitutes a part of the pump chamber, and a fitting having a discharge port, and when the impeller rotates at high speed, the discharge provided in the fitting is sealed from the suction port of the pump. In an electric pump that pumps fluid toward an outlet, the flow path is configured so that the fluid pumped by the impeller is collected in the flow path formed by the housing and the inclined groove provided on the outer periphery of the fitting. An inclined groove whose cross-sectional area gradually increases, and a through hole that guides the fluid accumulated along the inclined groove from the minimum cross-sectional area to the maximum cross-sectional area of the flow path to the discharge port. It is specifically configured to be provided in.

[Effect of idea]

Since the present invention is specifically configured as described above, the velocity energy given by the rotation of the impeller while the fluid flows along the inclined groove of the fitting can be efficiently converted into pressure energy, and the pump It can increase efficiency and improve flow rate vs. discharge pressure characteristics, and has excellent practical effects.

〔Example〕

An example of an electric pump according to an embodiment of the present invention will be explained in detail below with reference to FIGS. 2 and 3.

Fig. 2 is a sectional view of a side part of an electric pump showing an embodiment of the present invention, and Fig. 3 is a perspective view of fittings 1 to 12, 14, 15, 17 to 21, 23.
25 are the same or equivalent parts as in the conventional device shown in FIG. 1, and therefore their explanation will be omitted.

In FIGS. 2 and 3, 26 is a fitting fixed to the housing 1 by the screw 14, 27 is a discharge port provided in the fitting 26, and 28 is located near the outlet of the impeller 7 on the outer periphery of the fitting 26. This is a spiral inclined groove provided, which gradually connects the housing 1 and the fitting 26 over approximately one circumference according to the direction of rotation of the impeller 7.
The cross-sectional area (volume) of the flow path formed by the inclined grooves 28 gradually increases. 29 is a maximum volume portion of the inclined groove 28, and 30 is a through hole that communicates this maximum volume portion 29 with the discharge port 27 of the fitting 26.

Next, the operation of this embodiment device will be explained.

First, when the electric motor in the motor chamber 5 is driven by an external power input, the impeller 7 and the shaft 6 are driven.
rotates in a predetermined direction. This rotation of the impeller 7 causes the fuel 25 in the tank 17 to be sucked through the opening 20 of the housing 1 and from the suction port 21 of the pump, and is similar to the conventional device until it is sent to the pump chamber 3.

On the other hand, the fuel 25 thus delivered is sent from the pump chamber 3 to an inclined groove 28 provided on the outer periphery of the fitting 26, and the fuel 25 is gradually accumulated along this inclined groove 28 in the same direction as the rotation of the impeller 7. It goes around almost once and reaches the maximum volume part 30,
Fuel 25 is pumped through the through hole 29 toward the discharge port 27 . The fuel 25 thus sent out by the rotation of the impeller 7 passes through the pump chamber 3 and is sent into the inclined groove 28, and since this inclined groove 28 plays the role of the spiral chamber of a normal pump, the fuel 25 flows into this inclined groove. Since the velocity energy can be efficiently converted into pressure energy while flowing through the pump 28, the efficiency of the pump is improved and the flow rate vs. discharge pressure characteristics can be significantly improved.

In the above description, an electric pump that is immersed and installed in an aircraft fuel tank has been described, but it goes without saying that it can also be used for pumps for various fluids other than aircraft.

[Brief explanation of the drawing]

FIG. 1 is a side partial sectional view showing a conventional electric pump, FIG. 2 is a side partial sectional view showing an embodiment of the present invention, and FIG. 3 is a perspective view of a fitting showing an embodiment of the present invention. . In the figure, 1 is a housing, 3 is a pump chamber,
6 is the shaft, 7 is the impeller, 21 is the suction port, 2
5 is a fuel, 26 is a fitting, 27 is a discharge port, 28 is an inclined groove, 29 is a maximum volume portion as the maximum cross-sectional area of the flow path, and 30 is a through hole. In addition,
The same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] a shaft rotatably driven by an electric motor; an impeller fixed to a part of the housing at one end of the shaft that projects into the pump chamber; and an impeller that rotates integrally with the shaft; The electric pump has a fitting having a discharge port, and the impeller rotates at high speed to pump fluid from the suction port of the pump toward the discharge port. The cross-sectional area of the flow path is an inclined groove that gradually increases so that the fluid is accumulated in the flow path formed by the housing and the slope groove provided on the outer periphery of the fitting, and the minimum cross-sectional area of the flow path is An electric pump characterized in that a through hole is provided in the maximum cross-sectional area of the fitting to guide the fluid accumulated along the inclined groove from the maximum cross-sectional area to the discharge port.