JP3949191B2 - Fuel pumping unit - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a fuel pumping unit, which is provided with a tubular casing, in which a feed pump is fitted, the feed pump is rotationally driven by an electric drive motor, and the drive motor is Two disk-shaped bearing shells are guided inside the casing via a rotor shaft, these bearing shells being adjacent to the drive motor on both sides and of the cylindrical outer surface of the bearing shell. At least in part, it relates to a type that is preloaded and applied to the inner wall of the tubular casing.
[0002]
[Prior art]
Such a type of pumping unit is used, for example, to pump fuel from a reserve tank to an internal combustion engine of an automobile. From DE 4040002 a feed unit is already known in which a feed pump and an electric drive motor for driving the feed pump are arranged in a common tubular casing. In this case, the drive motor is supported by two bearing shells fixed to the casing via the rotor shaft. In this case, the end of the rotor shaft that enters the feed pump is coupled to the rotating wheel so as to rotate together with the rotating wheel of the feed pump, and rotates the rotating wheel. The feed pump is arranged in a common casing adjacent to the drive motor in the axial direction. The pump wall of the feed pump facing the drive motor forms an intermediate casing. A support portion for guiding the rotor shaft is disposed in the intermediate casing, and the outer peripheral surface in the radial direction outside the intermediate casing is applied to the inner wall of the common tubular casing with being preloaded.
[0003]
In this case, however, this known feed unit not only entails high manufacturing and assembly labor in the range of the intermediate casing, but also forms a second bearing shell when press-fitting the intermediate casing and When the cover that closes the casing on the opposite side is press-fitted, the tubular casing may be deformed unintentionally. This can interfere with the correct bearing of the rotor shaft on the casing or feed pump. Furthermore, the possible bulge or temperature-based expansion of the intermediate casing and cover, mostly made of plastic, further deforms the tubular casing.
[0004]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide an improved fuel pumping unit of the type described at the outset, in which the effort for manufacturing and assembly is reduced and the deformation of the casing is reduced. It is to be.
[0005]
[Means for Solving the Problems]
In order to solve this problem, in the configuration of the present invention, an annular gap is provided between the outer peripheral surface of the support shell and the inner wall of the tubular casing (1), and the outer peripheral surface of the support shell is arranged in the radial direction. A plurality of integrally molded portions (11) projecting in the above are provided, and these integrally molded portions (11) are preloaded and applied to the inner wall of the tubular casing (1), and the integrally molded portions are formed. Part (11) is arranged on the first bearing shell, which is formed by an intermediate casing (9) forming the wall of the feed pump, the intermediate casing (9) being It is fitted between the drive motor (3) and the feed pump, the intermediate casing (9) is provided with radial ribs (23), and the integral molding part (11) is provided with ribs (23). of And so it is located in the extension of the radial direction.
[0006]
【The invention's effect】
The fuel pumping unit according to the first aspect of the present invention has the advantage that it is possible to reliably prevent deformation or radial expansion of the tubular common casing when the bearing shell is press-fitted. . This is advantageously achieved by the fact that the outer diameter of the disc-shaped bearing shell is smaller by a predetermined dimension than the inner diameter of the tubular casing in the bearing shell housing area. Thereby, an annular gap remains between the cylindrical outer peripheral surface of the support shell and the inner wall of the tubular casing. In order to fasten the bearing shell in the tubular casing, a large number of integrally molded portions projecting in the radial direction are provided on the outer peripheral surface of the bearing shell. These integrally molded portions are preloaded with the feed unit assembled and applied to the inner wall of the tubular casing. Prior to press fitting the bearing shell into the tubular casing, the integral part projects beyond the inner diameter of the tubular casing. Due to elastic deformation or shear at the edge of the tubular casing, the one-piece molded part, preferably distributed evenly over the circumference, is adapted to the actual contour of the inner wall of the tubular casing when the bearing shell is press-fitted. . Therefore, the inner wall surface of the tubular casing may have a large dimensional error and does not need to be additionally processed after molding. This significantly reduces manufacturing effort. Furthermore, the labor of assembling can be reduced by obtaining the same holding force as before with a small press-fitting force. In this case, deformation of the tubular casing is reduced by reducing the press-fitting force. For example, deformation of the bearing shell due to bulges is likewise not transmitted to the tubular casing.
[0007]
In this case, the bearing shell is formed in a known manner by an intermediate casing provided between the electric drive motor and the feed pump and a cover for closing the casing on the side opposite to the feed pump. This cover is provided with a connecting pipe piece for the fuel line, and this cover can also be used as a brush holder for an electric drive motor. In this case, the integrally molded portion can be selectively provided on one or both of the bearing shells at the same time.
[0008]
Another advantage of the present invention is obtained by providing an inclined portion on the side surface of the integrally formed portion facing the press-fitting direction. Thereby, when the support shell is assembled to the tubular casing, good centering of the support shell can be obtained.
[0009]
A particularly good and uniform fit of the bearing shell in the tubular casing is achieved when the integral part is formed in a triangular, conical or projecting cross section that tapers radially outward. can get. This is because the wide range of the integrally formed portion prevents further elastic deformation under the operating conditions of the feed unit after press fitting.
[0010]
In order to ensure reliable deformation or shearing of a part of the integrally formed portion provided in the support shell when the support shell is press-fitted into the tubular casing, the support shell and thus the integral part provided integrally therewith are provided. The molding part is made of a material softer than the tubular casing. Advantageously, the bearing shell is formed as a plastic member.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
In the following, embodiments of the present invention will be described in detail with reference to the drawings.
[0012]
The unit shown in FIG. 1 for pumping fuel, preferably from a reserve tank to an internal combustion engine of a motor vehicle, has a tubular casing 1. The casing 1 is fitted with an electric drive motor 3 and a feed pump (not shown) that is rotationally driven by the drive motor 3. The drive motor 3 has a rotor shaft 5. The rotor shaft 5 is guided by two disk-shaped support shells adjacent to the drive motor 3 on both sides. Of these, the first bearing shell is formed by the intermediate casing 9, and the second bearing shell is formed by the cover 8. The cover 8 has a connecting pipe piece 7 for a fuel pipe leading to the internal combustion engine, and can be used as a brush holder for the electric drive motor 3. The intermediate casing 9 which is axially adjacent to the drive motor 3 on one side simultaneously forms a first pump chamber wall of a feed pump (not shown) in a known manner. The feed pump can be formed, for example, as a fluid pump having a rotating wheel that rotates within the wall of the pump chamber along the side passage. A rotating wheel (not shown) is in this case connected to the rotor shaft 5 so as to rotate with the end of the rotor shaft 5 which penetrates the intermediate pump 9 and enters the feed pump. It is rotationally driven by. In this case, fuel is sucked into the feed pump by a rotating wheel in a known manner. The fuel flows out from the feed pump through the pressure feed opening, flows along the drive motor 3, and is fed into a pressure feed line (not shown) that leads to the internal combustion engine in the connecting pipe piece 7 provided in the cover 8. .
[0013]
The disc-shaped intermediate casing 9, preferably enlarged from FIGS. 2 and 3, preferably made from plastic, has an annular step 13 on its outer circumferential surface. The annular step 13 divides the cylindrical peripheral surface of the intermediate casing 9 into a larger outer peripheral surface 15 and a smaller outer peripheral surface 17. In this case, a large number of integrally molded portions 11 protruding in the axial direction are arranged on the smaller outer peripheral surface 17.
[0014]
The common tubular casing 1 for housing the drive motor 3 and the feed pump has a stepped portion 19 on the inner wall in the range of the intermediate casing 9 as well. The step portion 19 divides the large diameter range from the small diameter range in the inner wall range of the tubular casing 1. In this case, the larger diameter of the inner wall of the tubular casing 1 is formed such that the larger cylindrical outer peripheral surface 15 of the intermediate casing 9 is fitted into the casing 1 so as to slide. The dimension of the integrally molded part 11 projecting in the radial direction provided on the smaller cylindrical outer peripheral surface 17 of the intermediate casing 9 is smaller than the diameter of the larger inner wall of the tubular casing 1. It is larger than the diameter of the smaller inner wall. Therefore, the distance for press-fitting the intermediate casing 9 to the casing 1 can be reduced to a minimum value. In this case, the sealing in the direction of the flow chamber 21 surrounding the drive motor 3 is performed by the axial contact of the surfaces of the step portions 19 and 13 provided in the tubular casing 1 and the intermediate casing 9.
[0015]
The integrally formed part 11, which is preferably formed in a triangular, conical or projecting shape with a cross section decreasing radially outwards, is distributed uniformly over the peripheral surface of the smaller outer peripheral surface 17. . When the rib 23 extending in the radial direction is provided in the intermediate casing 9, the integrally molded portion 11 is disposed in the radial extension portion of the intermediate casing 9.
[0016]
In order to simplify the assembly, the side face 25 facing the press-fitting direction is inclined, so that the tubular casing 1 is prevented from being inclined at the step portion 19 during press-fitting.
[0017]
Whether the integrally molded portion 11 projecting radially from the intermediate casing 9 is elastically deformed according to the material of the intermediate casing 9 when the intermediate casing 9 is press-fitted into the tubular casing 1 in the axial direction. Or the radially outward end is sheared. In this case, an annular gap (not shown) remains between the smaller outer peripheral surface 17 provided in the intermediate casing 9 and the inner wall of the tubular casing 1. The material thickness of the integrally formed part 11 increasing inward in the radial direction in this case ensures a reliable press-fit even when an alternating load is applied during operation of the pumping unit.
[0018]
Alternatively or additionally, the integrally molded portion 11 may be provided on the surface 27 of the cover 8. In this case, the seal inside the casing and the configuration of the individual stepped portions, the surfaces, and the integrally molded portion are performed in a manner similar to the configuration in the intermediate casing 9 shown in FIGS.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a fuel pumping unit according to the present invention.
FIG. 2 is a view showing an intermediate casing press-fitted to an annular casing.
FIG. 3 is a cross-sectional view of an intermediate casing.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Casing, 3 Drive motor, 5 Rotor shaft, 7 Connection pipe piece, 8 Cover, 9 Intermediate casing, 11 Integral molding part, 13 Annular step part, 15 Outer peripheral surface, 17 Outer peripheral surface, 19 Step part, 21 Flow chamber, 23 ribs, 25 sides, 27 sides

Claims (11)

A fuel pumping unit, which is provided with a tubular casing (1), a feed pump is fitted in the casing (1), and the feed pump is rotationally driven by an electric drive motor (3); The drive motor (3) is guided to two disk-shaped support shells inside the casing (1) via the rotor shaft (5), and these support shells are connected to the drive motors (3 ) And at least a part of the cylindrical outer peripheral surface of the support shell, which is preloaded against the inner wall of the tubular casing (1), An annular gap is provided between the outer peripheral surface and the inner wall of the tubular casing (1), and a large number of integrally molded portions (1) projecting radially on the outer peripheral surface of the bearing shell. ) Is provided with, these integrally molded portions (11) and prestressed has been allusion to the inner wall of the tubular of the casing (1), wherein the integrally molded portion (11) of the first bearing shell And the first bearing shell is formed by an intermediate casing (9) forming a wall of the feed pump, the intermediate casing (9) being connected between the drive motor (3) and the feed pump. The intermediate casing (9) is provided with a radial rib (23), and the integrally molded portion (11) is disposed in a radial extension of the rib (23). A fuel pumping unit characterized by comprising:   The integrally molded part (11) is arranged in a second bearing shell, which is formed by a cover (8) that closes the tubular casing (1) on the side opposite to the feed pump. 2. A fuel pumping unit according to claim 1, wherein the cover (8) has a connecting pipe piece (7) for the fuel line.   The fuel pumping unit according to claim 1 or 2, wherein the first bearing shell and the second bearing shell have integrally molded portions (11) projecting radially in their outer peripheral surfaces.   2. The fuel pumping unit according to claim 1, wherein the integrally formed portions (11) in the radial direction are uniformly distributed over the entire outer peripheral surface of the bearing shell.   The integrally molded portion (11) has a cross section that tapers outward in the radial direction, and the side surface (25) of the integrally molded portion (11) facing the press-fitting direction of the support shell. The fuel pumping unit according to claim 1, wherein the fuel pumping unit is inclined.   6. A fuel pumping unit according to claim 5, wherein the integrally molded part (11) has a substantially triangular cross section.   6. The fuel pumping unit according to claim 5, wherein the integrally molded part (11) has a conical profile.   6. The fuel pumping unit according to claim 5, wherein the integrally molded part (11) is formed as a protrusion protruding in the radial direction.   2. The fuel pumping unit according to claim 1, wherein the bearing shell is made of a material that is less rigid than the tubular casing.   2. The fuel pumping unit according to claim 1, wherein a radially outward end of the one-piece molded part is sheared when press-fitting the bearing shell into the tubular casing. .   The end of the one-piece molded part (11) facing outward in the radial direction is elastically deformed when the support shell is press-fitted into the tubular casing (1). Fuel pumping unit.

Images