JPH06323215A - Electric fuel pump - Google Patents

Abstract

PURPOSE:To improve flow performance at the time of room temperature without degrading the flow performance at the time of high temperature by providing a displaced route part in the middle of a fuel route corresponding to the outer peripheral part of an impeller, and by providing a vapor discharging port in the stagnation part in a dammed side. CONSTITUTION:After the pressure of the fuel introduced from a fuel inlet part 17 into a fuel route 15 is raised while it flows in the fuel route 15 by rotating an impeller 1 by driving a motor part 2, the fuel is discharged out of a fuel outlet part. A displaced route part 21 which is displaced by almost the same route cross section in the diametral direction of the route 15 is provided in the middle of the fuel route 15 corresponding to the outer peripheral part of the impeller 10. A vapor discharging port 23 communicating between the inside and the outside of the route is provided on the stagnation part of a dammed part by means of the displaced route part 21. After the vapor generated at high temperature is collected in the dammed side, the vapor is discharged from the vapor discharging port 23 to the outside of the route, and the flow performance at high temperature can thus be ensured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-tank type electric fuel pump mainly used in automobiles.

[0002]

2. Description of the Related Art A conventional example of an in-tank type electric fuel pump arranged in a fuel tank of an automobile or the like in a dipped state will be described with reference to FIG. The electric fuel pump includes a motor unit 2 incorporated in a cylindrical housing 1 as shown in the sectional view of the pump unit in FIG.
It is composed of a pump part 3 incorporated in the lower part thereof. The motor unit 2 includes an armature 5 coaxial with the housing 1, a magnet 6 attached to the inner peripheral surface of the housing 1, a pump cover 7 attached to the lower end of the housing 1, and an upper end of the housing 1 (not shown). And a motor cover attached to the section. The motor cover is provided with a fuel outlet section for connecting a fuel supply pipe to the automobile engine. The lower part of the shaft 5a of the armature 5 is rotatably supported by the pump cover 7 via a bearing 8, and the lower end of the shaft 5a extends to the pump part 3.

The pump section 3 is of a Wesco type (also called a cascade type, a vortex type, etc.) driven by the motor section 2 and has blade grooves (reference numeral omitted).
Two upper and lower disc-shaped impellers 10 having outer circumferences
have. The pump casing that houses the impeller 10 is composed of the pump cover 7, a center plate 13 and a pump body 14 that are sequentially located below the pump cover 7. Between the pump cover 7 and the center plate 13, and between the center plate 13 and the pump body 1.
The impellers 10 and 4 are housed respectively. Each impeller 10 is connected to the shaft 5a of the armature 5 by fitting. Further, in the pump casing, a lower C-shaped fuel passage 15 and an upper fuel passage 16 are formed in a substantially C-shape corresponding to the outer peripheral portion of each impeller 10.

The lower end of the fuel passage 15 communicates with a fuel inlet portion 17 provided in the pump body 14,
The end thereof communicates with the communication port 18 provided in the center plate 13. The upper end of the fuel passage 16 communicates with the communication port 18 of the center plate 13, and the end thereof communicates with the inside of the housing 1 through a pump outlet 19 provided in the pump cover 7. The fuel inlet 17, the communication port 18, and the pump outlet 19 are
Although they are shown to be on the same line in the drawing, in actuality, they are in a positional relationship in which they are displaced from each other by a predetermined angle.

In the electric fuel pump, the impeller 10 of the pump unit 3 rotates together with the armature 5 by driving the motor unit 2 using a battery (not shown) of the automobile as a power source. As a result, the fuel in the fuel tank is pumped up to the fuel passage 15 below the fuel inlet 17. The pumped fuel is pressurized by the rotation of the impeller 10 while passing through the lower fuel passage 15 and then the upper fuel passage 16, and is pumped from the pump outlet 19 to the housing 1.
After entering the inside and passing through the inside of the housing 1, it is discharged from the fuel outlet.

Further, in the pump body 14, FIG.
As shown in the plan view in (b), the lower fuel passage 1
The passage groove 120 forming the lower part of
7, a low-pressure side flow passage portion 121 expanded over a length capable of obtaining a predetermined boosting action, and a step portion formed at a downstream end portion of the low-pressure side flow passage portion 121 to reduce a passage cross-sectional area of the fuel passage 15. 124, and a high pressure side flow passage portion 122 formed from the step portion 124 to the communication port 18 and having a passage cross-sectional area smaller than that of the low pressure side flow passage portion 121. Further, the blocking side by the step portion 124 (so-called upstream side)
The stagnation portion is provided with a small-hole-shaped vapor discharge port 123 that communicates the inside and outside of the passage. Pump body 1
A rising wall 14 a having a height substantially equal to the thickness of the impeller 10 is formed in an annular shape on the outer peripheral portion of the ring 4. As a result, the vapor generated in the fuel passage 15 is removed from the step portion 12
Weir by 4 and vapor outlet 1 of the stagnation part
By discharging from 23 to the outside of the passage, deterioration of the flow rate performance due to vapor is prevented. It should be noted that, for example, Japanese Patent Publication No. 3-610 can be applied to such measures.
There is No. 38 publication.

[0007]

According to the above-mentioned prior art, since the passage cross-sectional area is enlarged in the low pressure side flow passage portion 121 from the fuel inlet portion 17 to the vapor discharge outlet 123, it is effective for fuel conveyance. Some parts do not work, and the flow rate performance at room temperature deteriorates. If the number of rotations of the motor is increased to compensate for the deterioration of the flow rate performance, the noise performance deteriorates.

Therefore, the present invention has been made to solve the above-mentioned problems, and an object thereof is an electric fuel pump capable of improving the flow rate performance at normal temperature without deteriorating the flow rate performance at high temperature. To provide.

[0009]

In the electric fuel pump of the present invention for solving the above-mentioned problems, a process in which the fuel introduced from the fuel inlet to the fuel passage flows through the fuel passage by rotating the impeller by driving the motor portion. In a Wesco type electric fuel pump that pressurizes at the fuel outlet and then discharges it from the fuel outlet, there is a shift passage part in the middle of the fuel passage corresponding to the outer peripheral part of the impeller, which has a substantially same passage cross-sectional area in the radial direction of the passage. A vapor discharge port that communicates the inside and outside of the passage is provided in the stagnation portion on the damming side of the offset passage portion.

[0010]

According to the above-mentioned means, since the shift passage portion is provided in the fuel passage corresponding to the outer peripheral portion of the impeller, the vapor generated at a high temperature is collected on the damming side of the shift passage portion and then It is discharged to the outside of the passage from the vapor discharge port in the stagnation portion, and thus the flow rate performance at high temperature is secured. Further, since the above-mentioned offset passage portion does not increase the passage cross-sectional area, it can be made into a short section to have a long effective length necessary for securing the flow rate, and therefore, the flow rate performance at room temperature is hardly adversely affected.

[0011]

Embodiments Embodiments 1 and 2 of the present invention will be described in order. Since each embodiment is a modification of a part of the conventional example, the modified part will be described in detail, and the parts which are considered to have the same or equivalent configuration as the conventional example are designated by the same reference numerals and overlapped. The description is omitted.

[First Embodiment] A first embodiment will be described with reference to FIGS. 1 and 2. 1 shows a pump cover, (a) is a plan view, (b) is a sectional view taken along line BB of (a), (c) is a sectional view taken along line CC of (a), (d). (A) is the DD sectional view taken on the line (a), and (e) is the EE line sectional view taken on the (a). 2 shows a pump portion of an electric fuel pump incorporating the pump cover of FIG.
(A) is sectional drawing, (b) is a principal part enlarged view of (a).
In the pump body 14 in which the fuel passage 15 corresponding to the outer peripheral portion of the lower impeller 10 shown in FIG. 2 is formed in cooperation with the center plate 13, the passage groove 20 forming the lower portion of the fuel passage 15 is As shown in FIG. 1, the fuel inlet portion 17 to the communication opening 18 are formed in an arc shape centered on the body axis. In the middle of the passage groove 20, there is provided a shift passage portion 21 which is displaced radially inward of the passage with a substantially same passage cross-sectional area. The shift passage portion 21 of this example is formed from the fuel inlet portion 17 over a section of about ± 15 ° with respect to about 180 °, that is, a section of about 30 °.

By forming the shift passage portion 21, a damming side step 22 is formed at the inner peripheral side downstream end of the shift passage portion 21, and a corner portion of the step 22 serves as a stagnation portion of fuel. A vapor discharge port 23 that communicates the inside and outside of the passage is formed in this stagnation portion.

As shown in FIG. 2B, also in the center plate 13, the passage groove 25 forming the upper portion of the fuel passage 15 corresponds to the passage groove 20 having the offset passage portion 21. It is formed with a shape.

According to the electric fuel pump described above,
Since the shift passage portion 21 is provided in the fuel passage 15 corresponding to the outer peripheral portion of the impeller 10, the vapor generated at a high temperature is collected on the damming side of the shift passage portion 21, and then the stagnation portion of the vapor is discharged. It is discharged from the outlet 23 to the outside of the passage. This ensures the flow performance at high temperatures. Further, since the shift passage portion 21 does not increase the passage cross-sectional area, it can be shortened to have a long effective length for securing the flow rate. Therefore, as compared with the conventional example in which the passage cross-sectional area of the fuel passage is increased, the number of portions that do not work effectively for fuel conveyance is reduced, so that the flow rate performance at normal temperature is improved.

FIG. 3 shows the test results of the flow rate characteristics of the example product and the conventional product at high temperature. The horizontal axis in the figure represents the elapsed time (minutes) of the operation, and the vertical axis represents the discharge flow rate (L / H) and the fuel temperature (° C). The straight line indicated by the chain double-dashed line in FIG. 5 indicates that the fuel temperature rises until a predetermined time elapses. The solid line in FIG. 5 is the flow rate characteristic of the example product, and the dotted line in the figure is the flow rate characteristic of the conventional product. Therefore, it can be seen that the discharge flow rate of the example product is larger than that of the conventional product over time.

FIG. 4 shows the test results of the flow rate characteristics of the example product and the conventional product at room temperature. The bar column A on the left side of the drawing is the discharge flow rate of the conventional product, and the bar column B on the right side of the drawing is the discharge flow rate of the example product. Therefore, it can be seen that the discharge amount Q of the example product is higher than that of the conventional product even at room temperature.

[Second Embodiment] A second embodiment will be described with reference to FIG. 5 shows the pump cover,
(A) is a plan view, (b) is a B ₁ -B ₁ line sectional view of (a), (c) is a C ₁ -C ₁ line sectional view of (a), (d) is D of (a) _1- D ₁ line sectional view, (e) is E _{1 of} (a)
It is a sectional view taken along line E ₁ . In this example, the shift passage portion 21 in the first embodiment is provided not on the radially inner side of the passage but on the outer side thereof. In this case, a weir-side step 22a is formed at the upstream end on the inner peripheral side of the shift passage 21, and a corner portion due to the step 22a becomes a stagnation portion of fuel. Therefore, the vapor discharge port 23 is provided in the stagnation portion. Also in this example, the same operational effect as in Example 1 can be obtained.

[0019]

According to the electric fuel pump of the present invention, unlike the conventional example in which the passage cross-sectional area of the fuel passage is increased, the flow rate performance due to the effect of collecting and discharging the vapor at a high temperature is ensured at room temperature. The flow performance is improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a pump body according to a first embodiment.

FIG. 2 is an explanatory diagram showing a pump portion of an electric fuel pump.

FIG. 3 is a flow rate characteristic diagram of the electric fuel pump at a high temperature.

FIG. 4 is a flow rate characteristic diagram of the electric fuel pump at room temperature.

FIG. 5 is an explanatory diagram showing a pump body according to a second embodiment.

FIG. 6 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 2 Motor part 10 Impeller 15 Fuel passage 17 Fuel inlet part 21 Shift passage part 23 Vapor discharge port

Claims (1)

[Claims] 1. A Wesco type electric fuel pump in which a fuel introduced from a fuel inlet to a fuel passage is boosted in the process of flowing through the fuel passage and then discharged from a fuel outlet by rotating an impeller by driving a motor portion. In the middle of the fuel passage corresponding to the outer peripheral portion of the impeller, there is provided a displacement passage portion that is displaced in the radial direction of the passage with substantially the same passage cross-sectional area, and inside and outside the passage at the stagnation side on the damming side by the displacement passage portion. An electric fuel pump provided with a vapor discharge port that communicates with each other.