PUMP IMPELLER

Abstract

An impeller, which is rotatable about an axis, includes an inlet shroud and a backing plate. An inlet orifice is defined by the inlet shroud, and a plurality of outlet orifices are radially outward of the inlet orifice. A plurality of vanes are disposed between the inlet shroud and the backing plate. The vanes are formed integrally as one-piece with the inlet shroud.

Description

TECHNICAL FIELD

This disclosure relates to impellers for fluid pumps.

BACKGROUND

Automobiles and other vehicles use pumps to pressurize fluids, increase the speed of fluids, or both.

SUMMARY

An impeller is provided, and is rotatable about an axis. The impeller includes an inlet shroud and a backing plate. An inlet orifice is defined by the inlet shroud, and a plurality of outlet orifices are located radially outward of the inlet orifice.

The impeller also includes a plurality of vanes, which are disposed between the inlet shroud and the backing plate. The plurality of vanes are formed integrally as one-piece with the inlet shroud.

The above features and advantages, and other features and advantages, of the present invention are readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out the invention, which is defined solely by the appended claims, when taken in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic, isometric view of an impeller, viewed from an inlet side;

FIG. 2 is a schematic, exploded, isometric view of the impeller of FIG. 1, viewed from a back side;

FIG. 3 is a schematic, isometric view of the assembled impeller of FIGS. 1 and 2, viewed from the back side;

FIG. 4 is a schematic, exploded, isometric view of an alternative impeller, viewed from a back side;

FIG. 5 is a schematic, isometric view of the assembled impeller of FIG. 4; and

FIG. 6 is a schematic graph illustrating operational results of the impeller shown in FIGS. 1-3 compared with a different impeller.

DETAILED DESCRIPTION

Referring to the drawings, wherein like reference numbers correspond to like or similar components wherever possible throughout the several figures, there is shown in FIG. 1 an impeller 10. A pump (not shown), such as a centrifugal pump, may use the impeller 10 to increase the pressure and flow of a working fluid (not shown).

While the present invention may be described with respect to automotive applications, those skilled in the art will recognize the broader applicability of the invention. Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” et cetera, are used descriptively of the figures, and do not represent limitations on the scope of the invention, as defined by the appended claims. Any numerical designations, such as “first” or “second” are illustrative only and are not intended to limit the scope of the invention in any way.

The impeller 10 is operatively attached to a driveshaft 12 and rotatable about an axis 14. As the driveshaft 12 rotates the impeller 10, the working fluid is pumped by accelerating the working fluid outward from the axis 14. The path of the working fluid is illustrated in FIG. 1 by inlet flow 16 and outlet flow 18. The kinetic energy of the impeller 10 is converted into pressure as outward movement of the working fluid is confined by a pump casing (not shown) radially outward of the impeller 10. In the view shown in FIG. 1, the impeller 10 generally operates while rotating in the counterclockwise direction.

The impeller 10 includes an inlet shroud 20 and a backing plate 22. A plurality of vanes 24 are disposed between the inlet shroud 20 and the backing plate 22. These vanes 24 transfer motion of the impeller 10 into motion or pressure within the working fluid. The vanes 24 are formed integrally as one-piece with the inlet shroud 20, such that the vanes 24 are not separately or subsequently attached to the inlet shroud 20.

The inlet flow 16 enters an inlet orifice 26 defined by the inlet shroud 20. The inlet orifice 26 is substantially co-axial with the driveshaft 12 and the axis 14. The inlet flow 16 may be a substantially contiguous flow or stream of the working fluid. The outlet flow 18 exits through a plurality of outlet orifices 28, which are radially outward of the inlet orifice 26 from the axis 14.

The impeller 10 may also be defined by a draft angle 30 formed on the vanes 24. The draft angle 30 opens from the inlet shroud 20 to the backing plate 22. A first distance 31 between a base end 32, which is proximate to the inlet shroud 20, of the vanes 24 is smaller than a second distance 33 between a plate end 34, which is distal to the inlet shroud 20, of the vanes 24.

As the inlet flow 16 enters the impeller 10, the flow of working fluid is generally parallel with the axis 14. However, as the outlet flow 18 exits the impeller 10, the flow of working fluid is generally perpendicular to the axis 14 (i.e., the flow is radial). This change in direction may be referred to as “turning” the working fluid. Because of the draft angle 30, the first distance 31 between the vanes 24 is smaller than the second distance 33. Therefore, as the working fluid turns, it is moving toward the second distance 33 and is moving from tighter space to freer space during the turn. Contrarily, if the draft angle 30 were reversed, the working fluid would be more constricted as it turns from axial flow to radial flow.

In the impeller 10 shown, the inlet shroud 20 and the vanes 24 may be formed as one-piece by a single-action mold. The single-action mold would separate from the inlet shroud 20 and the vanes 24 substantially in the direction of the axis 14.

Referring also to FIG. 2 and FIG. 3, and with continued reference to FIG. 1, there is shown another view of the impeller 10. FIG. 2 shows an exploded isometric view of the impeller 10, shown from a back side, which is generally opposite of the view shown in FIG. 1. FIG. 3 shows the impeller 10 in an assembled state from the same view as FIG. 2. The driveshaft 12 is removed from view in both FIG. 2 and FIG. 3.

The impeller 10 also includes a plurality of slots 36 formed in the backing plate 22. A plurality of tabs 38 are formed on the plate end 34 of the vanes 24. The tabs 38 are configured to mate with the slots 36. Therefore, the backing plate 22 and the vanes 24 are mated together, which may assist in carrying loads between the two components. The tabs 38 and the slots 36 may mate through a slip fit, an interference fit (such as by snapping into the slots 36), or by a deformation fit.

Referring now to FIG. 4 and FIG. 5, and with continued reference to FIGS. 1-3, there is shown an alternative impeller 110. FIG. 4 shows an exploded isometric view of the impeller 110, from a back side viewpoint. FIG. 5 shows an isometric view of the assembled impeller 110. In operation, the impeller 110 and the impeller 10 shown in FIGS. 1-3 may operate in substantially identical fashion.

The impeller 110 includes an inlet shroud 120 and a backing plate 122. A plurality of vanes 124 are disposed between the inlet shroud 120 and the backing plate 122. These vanes 124 transfer motion of the impeller 110 into motion or pressure within the working fluid. The vanes 124 are formed integrally as one-piece with the inlet shroud 120, such that the vanes 124 are not separately or subsequently attached to the inlet shroud 120.

Inlet flow of the working fluid enters an inlet orifice 126 defined by the inlet shroud 120. Outlet flow of the working fluid exits through a plurality of outlet orifices 128, which are radially outward of the inlet orifice 126.

The impeller 110 may also be defined by a draft angle formed on the vanes 124. The draft angle opens from the inlet shroud 120 to the backing plate 122, such that a base end 132 of the vanes 124 is wider than a plate end 134 of the vanes 124. In the impeller 110 shown, the inlet shroud 120 and the vanes 124 may be formed as one-piece by a single-action mold.

The impeller 110 also includes a plurality of slots 136 formed in the backing plate 122. A plurality of tabs 138 are formed on the end of the vanes 124, and are configured to mate with the slots 136.

In addition to mating the tabs 138 with the slots 136, the impeller 110 further includes an annular ring 140 formed on the opposing side of the backing plate 122 from the vanes 124. The annual ring 140 connects the plurality of tabs 138.

As shown in FIG. 4, a channel 142 may be formed in the backing plate 122. The channel 142 may house the annular ring 140, such that the annular ring 140 is flush with the backing plate 122. However, the annular ring 140 may alternatively be formed on the backing plate 122 without the channel 142.

In one illustrative manufacturing process for the impeller 110, after the inlet shroud 120 and the vanes 124 are formed as one-piece by the single-action mold, the tabs 138 are inserted into the slots 136 in the backing plate 122. Then, the annular ring 140 is overmolded onto the backing plate 122 and the plurality of tabs 138, such that formation of the annular ring 140 locks the tabs 138 to the backing plate 122.

Referring now to FIG. 6, and with continued reference to FIGS. 1-5, there is shown a schematic graph 200, which illustrates operational results of the impeller 10 shown in FIGS. 1-3 compared with a different, comparison impeller. The graph 200 shows the improved performance of the impeller 10 over the comparison impeller.

The comparison impeller does not have the draft angle 30 shown in FIGS. 1-3. The comparison impeller may have an opposite draft angle (opening from a backing plate toward an inlet shroud) or may be a foil impeller, which has vanes that are integral with, and bent outward from, the backing plate. Therefore, as the working fluid turns from axial flow to radial flow in the comparison impeller, the fluid becomes more constricted. However, in the impeller 10, the first distance 31 is smaller than the second distance 33, such that the working fluid is less constricted as it turns from axial flow to radial flow.

Flow rate values 202 are shown on the left side, in liters per minute. Hydraulic efficiency 204, in percentage, is shown on the right side. All values shown are illustrative, exemplary, and demonstrative, and the values are in no way limiting of the invention. To derive the data shown in the chart 200, the impeller 10 and the comparison impeller were simulated as operating at the same speeds, approximately 8750 revolutions per minute, and with the same working fluid, water-based coolant.

A bar 210 shows the flow rate of the impeller 10, and a bar 212 shows the flow rate of the comparison impeller. As shown in the chart 200, the impeller 10 yielded a higher flow rate over the comparison impeller.

A bar 214 shows the hydraulic efficiency of the impeller 10, and a bar 216 shows the hydraulic efficiency of the comparison impeller. As shown in the chart 200, the impeller 10 had improved hydraulic efficiency relative to the comparison impeller.

The detailed description and the drawings or figures are supportive and descriptive of the invention, but the scope of the invention is defined solely by the claims. While some of the best modes and other embodiments for carrying out the claimed invention have been described in detail, various alternative designs and embodiments exist for practicing the invention defined in the appended claims.

Claims

1. An impeller rotatable about an axis, comprising: an inlet shroud;a backing plate;an inlet orifice defined by the inlet shroud, and a plurality of outlet orifices radially outward of the inlet orifice; anda plurality of vanes disposed between the inlet shroud and the backing plate, wherein the plurality of vanes are formed integrally as one-piece with the inlet shroud.

2. The impeller of claim 1, further comprising: a draft angle formed on the plurality of vanes from the inlet shroud to the backing plate, such that a first distance between a base end of the plurality of vanes is smaller than a second distance between a plate end of the plurality of vanes.

3. The impeller of claim 2, further comprising: a plurality of slots formed in the backing plate; anda plurality of tabs formed on the plate end of the plurality of vanes, wherein the plurality of tabs are configured to mate with the plurality of slots.

4. The impeller of claim 3, wherein the inlet shroud and the plurality of vanes are formed as one-piece by a single-action mold.

5. The impeller of claim 4, further comprising: an annular ring formed on the opposing side of the backing plate from the plurality of vanes and connecting the plurality of tabs.

6. The impeller of claim 5, wherein the annular ring is formed by overmolding the annular ring onto the backing plate and the plurality of tabs.

7. An impeller rotatable about an axis, comprising: an inlet shroud;a backing plate;a driveshaft operatively attached to the backing plate, and configured to impart kinetic energy to the backing plate;an inlet orifice defined by the inlet shroud, and a plurality of outlet orifices radially outward of the inlet orifice;a plurality of vanes disposed between the inlet shroud and the backing plate, wherein the plurality of vanes are formed integrally as one-piece with the inlet shroud and the plurality of vanes, inlet shroud, and backing plate define the plurality of outlet orifices;a plurality of slots formed in the backing plate; anda plurality of tabs formed on a plate end of the plurality of vanes, wherein the plate end is adjacent the backing plate and the plurality of tabs are configured to mate with the plurality of slots.

8. The impeller of claim 7, further comprising: a draft angle formed on the plurality of vanes from the inlet shroud to the backing plate, such that a first distance between a base end of the plurality of vanes is smaller than a second distance between the plate end of the plurality of vanes.

9. The impeller of claim 8, wherein the inlet shroud and the plurality of vanes are formed as one-piece by a single-action mold.