JPH02283894A - Westco pump - Google Patents

Abstract

PURPOSE:To accurately adjust radial clearance by fixing impellers to a pump shaft, adjusting the distance between the peripheries of the impellers and the bulkhead of a spacer to the specified value and then welding the spacer to the end plate of the bulkhead. CONSTITUTION:A motor driven fuel pump comprises an electric motor 2 and a Westco pump 4 connected by a shaft 6. The pump 4 has e plurality of pump chambers 21 and 22, in the interior of which a plurality of impellers 30 and 32 are contained respectively. The pump chamber 21 is composed of a body 10, spacer 12, and intermediate plate 14. In addition, another pump chamber 22 consists of the intermediate plate 14, a spacer 16, and a bulkhead 18. In this case, the radial clearance between the impeller 32 and the bulkhead 18 of the spacer 16 is adjusted to the specified dimension, and then the epacer 16 is welded to the bulkhead 18. This improves the sealability and efficiency of the pump 4.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to improvements in Wesco pumps, and particularly proposes a pump structure that has high pump efficiency and can be produced at low cost.

The pump according to the present invention is placed in a fuel tank of a vehicle and is suitably used as a pump for pumping fuel to an engine.

[Prior Art] Electric fuel pumps installed in the fuel tank of a vehicle are required to be downsized to improve installation ease. In order to reduce the external size and satisfy the pump performance, it is necessary to make the external size of the impeller as large as possible.In the conventional technology, considering the above points, an electric motor with the structure shown schematically in Fig. Fuel pumps are often used. The prior art will be explained with reference to this. In the figure, 2 is a me machine part, 4 is a pump part of a Wesco pump, and both are connected by a shaft 6. The pump section 4 has a first pump chamber 21 composed of a body 10, a first spacer 12, and an intermediate plate 14, and a second pump chamber 22 composed of an intermediate plate 14, a second spacer 16, and a partition wall 18. Here, the partition wall 18 is a partition wall that separates the pump section 4 and the electric motor section 2, and a bearing 19 that supports the shaft 6 of the electric motor 2 is fixed thereto. A first pump rotated by the shaft 6 is provided inside the first pump chamber 21 and the second pump chamber 22.
An impeller 30 and a second impeller 32 are housed. The entire pump section 4 and electric motor section 2 are housed within a bong 1 housing 8.

When the electric motor rotates and the impeller rotates, fuel is sucked in from the suction boat 40, pressurized in the first pump chamber 21, roughly pressurized in the second pump chamber 22, and passed through the fuel passage 42 to the electric motor section 2. enter the interior space of. Then, while cooling the electric motor 1112 inside the electric motor 2, it is discharged from the discharge port 44 and sent to the engine.

The sealing action in the axial direction of the pump is performed between the illustrated E surface of the first impeller 30 and the illustrated lower surface of the body 10 (thrust clearance) in the first pump chamber 21, and between the first impeller 30 and the illustrated lower surface of the body 10.
In the second pump chamber 22, the thrust clearance between the illustrated upper surface of the second impeller 32 and the illustrated lower surface of the intermediate plate 14, and the illustrated lower surface of the second impeller 32 and the partition wall 18. This is done by the thrust clearance on the top surface shown in the figure.

Also, the sealing action in the circumferential direction of the pump is performed by the first pump chamber 21.
Then, the minimum clearance (radial clearance) between the outer periphery of the first impeller 30 and the first spacer 12, and the second pump chamber 22.
This is achieved by the radial clearance between the second impeller 32 and the second spacer 16. In order to increase pump efficiency, it is important to improve the sealing performance of the pump chamber.

Therefore, it is desirable to make the thrust clearance and radial clearance as small as possible.

In the prior art, there is a partition wall 18 in the pump housing 8,
Second spacer 16, intermediate plate 14, first spacer 1
2. The body 10 etc. are fixed by press-fitting, and appropriate radial clearance and thrust clearance are ensured by manufacturing precision of individual parts.

[Problems to be Solved by the Invention] However, according to this method, in order to improve pump efficiency, it is necessary to improve the accuracy of individual parts, specifically the dimensional accuracy of the inner wall of the pump housing 8, and the concentricity of the bearing 19 with respect to the partition wall 18. It is necessary to improve the manufacturing accuracy of individual parts, such as the outer dimensions and inner diameter dimensions of the first spacer 12 and the second spacer 16, and the coaxiality and dimensions of the inner diameter and outer diameter of the first impeller 30 and the second impeller 32. In particular, when pumping capacity is increased, the diameters of the first impeller 30 and the second impeller 32 become larger, and higher precision of the parts is required.

The present invention is based on the above knowledge, and an object of the present invention is to improve pump efficiency, quality, and reliability while maintaining the manufacturing precision of parts as before.

[Means to solve the problem] This problem is solved by a Wesco pump with the following structure.

This Wesco pump has a pump shaft.

The pump further includes a first end plate that pivotally supports the pump shaft.

It has a second end plate roughly opposing the first end plate.

It also has spacers. The spacer has a substantially flat cylindrical shape and is interposed between the first and second end plates. A partition wall is provided on a part of the inner periphery.

It also has an impeller. The impeller is rotated by the pump shaft within a pump chamber defined by the first and second end plates and the spacer.

The impeller is attached to the pump shaft, and the spacer is fixed to the first end plate by welding with the distance between the outer periphery of the impeller and the partition wall of the spacer adjusted to a predetermined value.

[Function] When fixing the spacer, after adjusting the radial clearance between the outer periphery of the impeller and the partition wall of the spacer, the spacer is welded and fixed to the first end plate constituting the pump chamber. Therefore, the radial clearance can be accurately and reliably maintained at the desired value. Furthermore, since the spacer is not press-fitted into the pump housing, there is no need for it to be in close contact with the pump housing, and the material can be freely selected separately from each member.

[Example] Examples will be specifically described below with reference to the drawings.

1 to 9 show a first embodiment of the present invention. Note that FIG. 1 shows the attitude of the pump during the manufacturing process, and it is often used with the pump turned upside down.

Figure 1 shows a cross-sectional view of an electric fuel pump.
Electric! tlli2 and a pump section 4 in the form of a Wesco pump. The electric V3 machine 2 and the pump section 4 are connected by a shaft 6. Note that this embodiment shows an example of a two-stage pump.

The pump section 4 has a first pump chamber 21 and a second pump chamber 22. The first pump chamber 21 is connected to the body 10 and the first
It is composed of a spacer 12 and an intermediate plate 14.

The second pump chamber 22 includes an intermediate plate 14 and a second spacer 1.
6 and a partition wall 18. A first impeller 30 and a second impeller 32 are housed inside the first pump chamber 21 and the second pump chamber 22, respectively. The first impeller 30 and the second impeller 32 are rotated by the shaft 6.

The entire pump section 4 is housed inside a cylindrical pump housing 8.

The partition wall 18 constituting one surface of the inner wall in the axial direction of the second pump chamber 22 also serves as a bearing for the electric motor I12, and has an annular shaft hole formed in the center thereof. A cylindrical bearing 19 is housed inside the shaft hole, and the shaft 6 of the electric motor 2 passes through the inside of the bearing 19 and is connected to the pump section 4. The partition wall 18 has a flow path 42 for guiding the fuel discharged from the second pump 9!22 into the electric motor 2, and is fixed by being press-fitted into the pump housing 8. This distance M118 corresponds to the first end plate in the claims.

The second spacer 16 constitutes the inner wall of the second pump chamber 22 in the circumferential direction and regulates the dimension in the axial direction.

The second impeller 32 is connected to the second pump chamber 22 by the electric motor 2.
By being rotated inside the cylinder, it works to give the fuel a flow velocity. The second impeller 32 cannot rotate relative to the shaft 6, but is assembled so as to be slidable in the axial direction. 2 and 3 show the positional relationship between the second spacer 16 and the second impeller 32. FIG. The second spacer 16 has a flat cylindrical shape, and has a stepped portion 17 formed on a part of its inner circumference.

This step 17 functions as a partition wall.

In order to improve the efficiency of the pump, it is necessary to improve the sealing performance of the pump, and for this purpose, the radial clearance between the second impeller 32 and the partition wall 17 of the second spacer 16 should be set to 100 μm or less. is necessary. This is too small to be illustrated. In this embodiment, after measuring this radial clearance with a thickness gauge and adjusting it to a specified dimension, the second spacer 1
6 is temporarily fixed to the partition wall 18 at two locations (A, B) by laser welding. Here, recesses (A, B) for laser welding are provided on the surface of the second spacer 16 opposite to the partition wall 18. By projecting a laser into this recess,
The portion onto which the laser is projected is melted by heat, and the melting by the laser reaches the contact portion with the partition wall 18 through the thickness of the second spacer 16, melting a part of the partition wall 18, and completing the welding. In the case of laser welding, only the welded portion is heated to high temperature, so that the heat does not cause deformation of the member or deterioration of the surface treatment performance of the member. Therefore, the precision of radial clearance etc. does not deteriorate due to laser welding.

The intermediate plate 14 connects the first pump to 21 and the second pump chamber 2.
It is a partition separating the second pump chamber 2 and the second pump chamber 2.
It is also a member constituting one surface of the inner wall in the axial direction of No. 2. This corresponds to the second end plate in the claims of the second pump chamber. The assembly of the intermediate plate 14 is shown in FIGS. 4 and 5.

The intermediate plate 14 has grooves on both sides of the first pump chamber 21 side and the second pump chamber 22 side, which form a flow path through which the fuel passes, in portions corresponding to the vanes of the impeller outer periphery. and the first
The grooves on both sides of the pump seedling 21 side and the second pump chamber 22 side communicate with each other through the through hole 15. Fuel exiting the first pump chamber 21 through the through hole 15 is sent into the second pump chamber 22. After the intermediate plate 14 is positioned,
The second spacer 16 has already been temporarily fixed by laser welding.
It is temporarily fixed by laser welding at two locations (C and D).

Here, a recess (C) for laser welding is provided on the surface of the intermediate plate 14 opposite to the second spacer 16.

D) is provided. The welding method is the second spacer 1.
6 and the partition wall 18 are welded together.

The first spacer 12 constitutes the inner wall of the first pump chamber 21 in the circumferential direction, and also regulates the dimension in the axial direction.

The first impeller 30 is connected to the first pump chamber 21 by the electric motor 2.
By being rotated inside the cylinder, it works to give the fuel a flow velocity. The first impeller 30 is attached to the shaft 6 so that it cannot rotate relative to the shaft 6 and is slidable in the axial direction. 6th
The relationship between the first spacer 12 and the first impeller 30 is shown in FIG. In order to improve the sealing performance of the pump, it is necessary to set the radial clearance between the first impeller 30 and the partition wall 13 of the first spacer 12 to 100 μm or less. In this example, after measuring the radial clearance with a thickness gauge and adjusting it to the specified dimension, the first
The spacer 12 is temporarily fixed by laser welding at two locations (E, F) to the intermediate plate 14, which has already been temporarily fixed by laser welding.

Here, the surface of the first spacer 12 that is not in contact with the intermediate plate 14 has recesses (E, F) for laser welding.
) is provided. The welding method is the same as that for welding the intermediate plate 14 and the second spacer 16.

The body 10 constitutes one surface of the inner wall in the axial direction of the first pump chamber 21, and at the same time serves as a lid for the pump section 4. It also has a suction boat 40 for sucking fuel. body 1
After each part of the pump part 4 is temporarily fixed in the pump housing, the pump part 0 is finally press-fitted into the pump housing and fixed therein.

In the second pump to 22, the intermediate plate 14 itself does not pivotally support the pump shaft 6. However, the intermediate plate 14 is fixed to the partition wall 18 via the second spacer 16, and the pump shaft 6
It is supported by the shaft.

8 and 9 show a method of adjusting the radial clearance described above. Although the case of the second pump seedling 22 is shown here as an example, the adjustment is performed in the same manner in the case of the first pump.

First, the septum 18 is press-fitted into the pump housing.

Next, a second impeller 32 is attached to the shaft 6 of the electric motor 2 passing through the bearing 19 located at the center of the partition wall 18.
is set so that it cannot rotate relative to each other and is slidable in the axial direction.

In this state, the second spacer 16 is temporarily set outside the second impeller 32 in the circumferential direction.

Next, the thickness gauge 51 is sandwiched between the partition wall 17 of the second spacer 16 and the second impeller 32, and in this state,
Slightly move the second spacer 16 in the circumferential direction.

and adjust the radial clearance to the specified value. In order to slightly move the second spacer 16 in the circumferential direction of the second impeller 32, a dedicated jig 50 is used. This jig 50 is inserted into the second spacer 16 from the outside of the pump housing 8.
It consists of two arms and a fixing part that fixes the arms so that it can be moved. The second spacer 16 is provided with two holes facing each other with a diameter in between, into which the tips of the two arm portions of the jig 50 can fit. With this jig 5o, the radial clearance can be efficiently adjusted from the outside of the pump housing 8.

According to the first embodiment described above, the radial clearance can be accurately and reliably set to a desired value.

What is press-fitted and fixed into the pump housing 8 are the partition wall 18 and the body 10 that constitute the end of the pump section 4.
Since the intermediate first spacer 12, second spacer 16, and intermediate plate 14 are temporarily fixed by laser welding,
It is not necessary to bring it into close contact with the pump housing 8. Therefore, even if there is a problem such as deformation of the pump housing 8 due to the application of external pressure, deformation of the spacer can be prevented to some extent and accuracy of radial clearance etc. can be ensured.

10 to 12 show a laser welding method in a second embodiment of the present invention. In this method, an opening 80 is provided in the pump housing 8, and the first spacer 12,
This is a method of welding by directly projecting a laser onto the contact portion of the second spacer 16 and the intermediate plate 14.

According to this method, the welded part can be visually checked from the outside, so the reliability of welding can be improved.

Furthermore, there is no need to provide a recess for laser welding in the member.

[Effect of the Invention 1] As a result, when temporarily fixing the spacer, the radial clearance can be accurately adjusted to the required dimension, and the quality and reliability of the pump are improved.

In addition, it is not necessary to increase the manufacturing precision of parts more than necessary in order to improve pump efficiency, and it is very economical.

Furthermore, since there is no need for the spacer to be in close contact with the inner wall of the pump housing, even if the pump housing is deformed due to external pressure, problems such as deformation of the spacer and deterioration of accuracy can be prevented to a certain degree.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electric fuel pump according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line ■-■ in FIG. 1, FIG. The figures are ': IV-TV sectional view of Figure 51, Figure 5 is a sectional view taken along V-V of Figure 4, Figure 6 is a VT-Vl arrow view of Figure 1, and Figure 7 is Figure 6. The ■-■ cross-sectional view of FIG. 8 is the electric twisting f! according to the present invention. 1. A plan view of the radial clearance adjustment method for a pump, Figure 9 is IX-I in Figure 8.
10 is a plan view of an electric fuel pump according to a second embodiment of the present invention, and FIG. 11 is a 10tffi(1)X sectional view.
I-XIIIi side view, Figure 12 is xm-xt in Figure 11
13 is a sectional view of an electric fuel pump according to the prior art. 2...Electric motor section 4...Pump section 6...Shaft 8...Pump housing 10...Body 12...First spacer υ 14...Intermediate plate 16...Second spacer 18 ...Partition wall 30...First impeller 32...Second impeller

Claims (1)

[Scope of Claims] A pump shaft, a first end plate that pivotally supports the pump shaft, a second end plate opposite to the first end plate, and between the first and second end plates. in a pump chamber defined by a substantially flat cylindrical spacer having a partition wall on a part of its inner periphery, and the first and second end plates and the spacer;
In a Wesco type pump having an impeller rotated by the pump shaft, the impeller is attached to the pump shaft, and the spacer is adjusted to a predetermined distance between the outer periphery of the impeller and the partition wall of the spacer. A Wesco pump characterized by being fixed to a first end plate by welding.