JPH07208374A - Impeller type pump - Google Patents

Abstract

PURPOSE:To reduce the leakage of fuel on the discharge side while keeping pressure balance between the upper and lower faces of an impeller so as to improve pump efficiency by complicating the leak flow passage of fuel on the discharge side, and increasing seal parts. CONSTITUTION:This impeller type pump is integratedly provided with a motor part and a pump part, and fuel pressure is raised by driving to rotate a disc-like impeller 1 rotatably provided in the case 4 of the pump part by means of the motor part. It is also provided with annular seal parts 7 on the sliding faces between the impeller 1 and the case 4, and communicating holes 10 penetratingly provided on the impeller 1, the seal part 7 is formed into a multiple annular form, and the communicating hole 10 is arranged on the position corresponding to respective seal parts 7.

Description

Detailed Description of the Invention

[0001]

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

[0002]

As is well known, an impeller type pump is also called a Wesco type or a circumferential flow type pump, and is integrally provided with a motor section and a pump section, and is rotated in a case of the pump section. The fuel pressure is increased by rotating a disc-shaped impeller, which is provided so as to be driven by the drive of the motor section (for example, see Japanese Utility Model Laid-Open No. 63-190586). An example of a conventional pump part structure of such a pump is shown in FIG. In the figure, (a) is a schematic sectional view of the pump portion, and (b) is a sectional view taken along line BB of (a). As shown in the figure, the impeller 1 has a disk shape and has a large number of blade grooves 2 on the outer peripheral portions of both end surfaces (front and back surfaces) thereof. The impeller 1 is connected to a shaft 3 of an armature of a motor unit, which is an electric motor (not shown).
Further, a case 4 in which the impeller 1 is rotatably installed in two upper and lower stages is provided with a flow channel groove 6 forming a fuel flow channel 5 corresponding to the outer peripheral portion of the impeller 1 in each stage. In addition, in the case 4, an inlet 9 for sucking fuel into the lower fuel flow path 5, a communication port (not shown) for flowing fuel from the lower fuel flow path 5 to the upper fuel flow path 5, an upper fuel flow path 5, a discharge port for discharging fuel from the motor part to the inside of the motor part, and a pump discharge port for discharging fuel from the inside of the motor part to a fuel supply pipe to the engine are provided.

An annular seal portion 7 having a seal surface width S is provided on the sliding surface of the impeller 1 and the case 4, and the seal portion 7
A communication hole 10 is provided in the vicinity of the axial center of the impeller 1 corresponding to the inside. The seal portion 7 refers to a clearance gap portion suitable for ensuring smooth rotation of the impeller 1 and preventing fuel leakage from the fuel passage 5 to the sliding surface toward the axial center of the impeller. Further, the communication hole 10 is provided with a fuel well 11 for containing the fuel leaked from the seal portion 7.
Is provided in order to balance the pressure applied to the upper and lower surfaces of the impeller 1. An impeller having such a communication hole is also disclosed in Japanese Utility Model Laid-Open No. 63-190586.

[0004]

In the conventional pump described above, for example, the fuel on the discharge side in the motor portion is the shaft 3
When it leaks into the fuel well 11 along the inlet, the fuel passes through the lower seal portion 7 and the suction port 9 as shown by the arrow in the figure.
If the fuel discharge pressure escapes, pump efficiency will drop. This is the communication hole 10 of the impeller 1.
It is considered that the upper and lower impeller accommodating spaces are communicated with each other through the fuel well 11 and that the seal portion 7 has one surface.

Therefore, the present invention has been made to solve the above-mentioned problems, and its purpose is to make the pressure between the upper and lower surfaces of the impeller by increasing the number of seal portions and the leakage passage of the fuel on the discharge side complicated. An object of the present invention is to provide an impeller type pump that can improve the pump efficiency by reducing the leakage of fuel on the discharge side while maintaining the balance.

[0006]

According to the present invention for solving the above-mentioned problems, a motor and a pump unit are integrally provided, and a disc-shaped impeller rotatably provided in a case of the pump unit is used for the motor. In an impeller type pump for increasing fuel pressure by rotating by driving the portion, an annular seal portion provided on a sliding surface of the impeller and a case and a communication hole penetrating the impeller are provided, and the seal portion is multiplexed. The communication holes are formed in an annular shape, and the communication holes are arranged at positions corresponding to each other between the seal portions.

[0007]

According to the above-mentioned means, since the seal portion is formed in the multiple annular shape, the seal portion is increased. Further, since the communication holes are arranged at the positions corresponding to each other between the seal portions, the discharge side fuel leakage flow path becomes a complicated flow path passing through the communication holes.

[0008]

EXAMPLES Examples 1 to 5 of the present invention will be described in order. [First Embodiment] A first embodiment will be described with reference to FIG. In the figure, (a) is a schematic sectional view of the pump portion, and (b) is a sectional view taken along line BB of (a). Since this example 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 be the same as or equivalent to those of the conventional example will be denoted by the same reference numerals and duplicate description will be omitted. . Further, the same concept is applied to the following embodiments, and a duplicate description will be omitted. In the impeller 1 in this example,
The annular groove 1 is formed by dividing the seal portion 7 of the conventional example into two.
2 are provided symmetrically on the front and back sides, and the seal portion 7 on each surface is formed in a double annular shape. Further, the communication hole 10 in the vicinity of the shaft center portion existing in the impeller 1 of the conventional example is eliminated,
The communication hole 10 is formed in the bottom surface of the annular groove 12 again. The communication holes 10 are located at positions corresponding to each other between the inner seal portion 7 and the outer seal portion 7, and an appropriate number, eight in this example, are arranged on the same circumferential line at equal intervals.

According to the impeller type pump of this embodiment, since the seal portion 7 is formed in the double ring shape, the seal portion 7 is increased to two places as compared with the conventional example. With the increase in the number of the seal portions 7, the communication holes 10 are arranged at positions corresponding to each other between the inner seal portion 7 and the outer seal portion 7, so that the pressure balance between the upper and lower surfaces of the impeller 1 can be maintained. The leakage flow path of the fuel on the discharge side becomes a complicated flow path passing through the communication hole 10 as shown by an arrow in the figure.

Explaining this point in detail, in the conventional example shown in FIG. 7, the fuel well 11 in the peripheral portion of the shaft 3 is divided by the upper and lower impellers 1, but the communication hole 10 is formed in the fuel well 11 portion. Due to the presence of, the pressure in each partition becomes uniform, so to speak, the pressure in the fuel well 11 becomes the discharge side fuel pressure. On the other hand, in the embodiment shown in FIG. 1, the fuel well 11 in the peripheral portion of the shaft 3 is divided by the upper and lower impellers 1, but the communication hole 10 does not exist in the fuel well 11 portion. Therefore, looking at the leakage flow path of the fuel on the discharge side, from the fuel well 11 on the upper side of the upper stage impeller 1, the inner peripheral side seal portion 7 on the upper side of the upper stage, the annular groove 12 on the upper side of the impeller 1, the communicating hole 10, the lower side of the impeller 1 are seen. Side annular groove 12, upper stage lower side inner peripheral side seal portion 7, fuel well 11 between both stages, lower stage upper side inner peripheral side seal portion 7, same impeller 1 upper annular groove 1
2, the communication passage 10, the annular groove 12 on the lower side of the impeller 1, and the outer peripheral side seal portion 7 on the lower side of the lower stage to the suction port 9 form a complicated flow path. Since the leakage passage of the fuel on the discharge side is complicated in this way, a labyrinth effect for the fuel leakage of the fuel on the discharge side can be obtained, so that the pump efficiency is improved.

FIG. 2 is a characteristic diagram showing the relationship between the pump rotation speed (rpm) of the impeller type pump and the pump discharge flow rate (L / h). The solid line in the figure shows the characteristic of the first embodiment, and the dotted line shows the characteristic of the conventional example. This example has a larger flow rate value at the same rotation speed than the conventional example. The discharge efficiency, that is, the pump efficiency is improved.

[Second Embodiment] A second embodiment will be described with reference to FIG. In addition to FIG. 3, in FIG. 4 to FIG. 6 showing the main part explanatory views of the following embodiments, (a) is a schematic sectional view of the pump part, and (b) is a partially broken impeller. It is a plane sectional view shown, and each figure shows the main part for one stage of the pump part. In this example, the annular groove 12 of the impeller 1 of Example 1 is provided in a double annular shape, the seal portion 7 is formed in a triple annular shape, and the communication holes 10 are formed in the bottom surface of each annular groove 12. That is, Example 1
Rather, one more seal portion 7 is added to further reduce fuel leakage on the discharge side.

[Third Embodiment] In the third embodiment, as shown in FIG. 4, an annular groove 12 is formed on the wall surface of the case 4, and the communication hole 10 is formed in the impeller 1 at a position corresponding to the bottom surface of the annular groove 12. Is installed throughout.

[Embodiment 4] In Embodiment 4, as shown in FIG. 5, a double annular ring-shaped groove 12 is formed on the wall surface of the case 4, and the impeller 1 corresponds to the bottom surface of each ring-shaped groove 12. The communication hole 10 is provided at the position of.

[Embodiment 5] As shown in FIG. 6, Embodiment 5 is the same as Embodiment 1 except that an annular groove 12 corresponding to the annular groove 12 of the impeller 1 is also formed on the wall surface of the case 4. Is.

[0016]

According to the impeller type pump of the present invention, the number of seals is increased and the leakage passage of the fuel on the discharge side is complicated, so that the pressure of the fuel on the discharge side is maintained while maintaining the pressure balance between the upper and lower surfaces of the impeller. Leakage can be reduced, thus improving pump efficiency.

[Brief description of drawings]

FIG. 1 is an explanatory view of a main part showing a first embodiment.

FIG. 2 is a characteristic diagram showing the relationship between pump rotation speed and fuel flow rate.

FIG. 3 is an explanatory view of a main part showing a second embodiment.

FIG. 4 is an explanatory diagram of a main part showing a third embodiment.

FIG. 5 is an explanatory view of a main part showing a fourth embodiment.

FIG. 6 is an explanatory diagram of a main part showing a fifth embodiment.

FIG. 7 is an explanatory diagram showing a conventional example.

[Explanation of symbols]

 1 Impeller 4 Case 7 Seal part 10 Communication hole

Claims (1)

[Claims] 1. A motor unit and a pump unit are integrally provided,
In an impeller type pump that boosts fuel pressure by rotating a disc-shaped impeller rotatably provided in the case of the pump unit by driving the motor unit,
An annular seal portion provided on the sliding surface of the impeller and the case and a communication hole penetrating the impeller are provided, and the seal portion is formed in a multiple annular shape, and the communication is performed at positions corresponding to each other of the seal portions. Impeller pump with holes.