HYDRODYNAMIC TORQUE CONVERTER

Abstract

The invention relates to a hydrodynamic torque converter having a pump shell including blades, a turbine shell including blades, a torus-shaped flow cycle. The blades are configured to be attached at the respective shells through inner walls and the inner walls of the turbine shell and of the pump shell form an inner torus with outer surfaces facing the flow cycle and an end of an extension of the inner wall of at least one shell and an end of an extension of an adjacent shell are disposed in a plane and extend over one another and define a gap between one another. A transition from the extensions is configured to be hydrodynamically smooth.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority from German Patent Application No. 10 2009 051 221.7, filed Oct. 29, 2009, which application is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The invention relates to a hydrodynamic torque converter.

BACKGROUND OF THE INVENTION

Hydrodynamic torque converters of this type are generally known. They include a torus-shaped fluid flow cycle formed by a pump shell, a turbine shell and possibly a stator shell and fluid included in the fluid cycle. Blades are disposed at each of the shells of the pump shell and the turbine shell, where the blades are attached at the respective shells through suitable walls and the blades are supported at the shells. The walls respectively include inner walls, where the inner walls of the pump shell together with the inner walls of the turbine shell and possibly the inner walls of the stator shell form an inner torus, where the blades of the shells can interact with the fluid flow in the flow cycle outside of the inner torus. The shells are proximal to one another along the torus-shaped flow cycle with a slot left between them. Fluid flowing in the flow cycle, however, can move into the inner portion of the inner torus through the slot.

German Patent No. 198 03 173 B4 illustrates a configuration of an extension of the inner wall of a shell configured to prevent a leakage flow from the torus-shaped flow cycle into the inner portion of the inner torus. Thus, an end of the extension of the inner wall of a shell reaches over an end of an extension of an adjacent shell with a radial gap formed between the ends. This facilitates shielding the flow cycle against the inner portion of the inner torus and reduces the leakage flow. However, the respective outer surfaces of the extensions facing the flow cycle are radially offset relative to one another, which disturbs the fluid flowing in the torus-shaped flow cycle and reduces the efficiency of the hydrodynamic torque converter.

Thus, it is the object of the invention to improve the efficiency of a hydrodynamic torque converter.

The object is achieved through a hydrodynamic torque converter.

BRIEF SUMMARY OF THE INVENTION

Accordingly, a hydrodynamic torque converter is proposed which comprises a pump shell and a turbine shell, respectively, including blades and a torus-shaped flow cycle, wherein the blades are configured to be attached at the respective shells through inner walls and the inner walls of the turbine shell and of the pump shell form an inner torus with outer surfaces facing the flow cycle. An end of an extension of the inner wall of at least one shell and an end of an extension of an adjacent shell are disposed in a plane or reach over one another, e.g., in a form of an overlap. The ends define a gap between one another and a transition from the extensions is configured to be hydrodynamically smooth. For example, a theoretical fluid element of the flow in the flow cycle in the portion of the transition and in particular over the gap is essentially straight or only slightly curved. This helps to reduce vortices of the flow in the flow cycle in the transition portion which can cause a reduction of the flow resistance in the flow cycle and which improves the efficiency of the hydrodynamic torque converter.

In an embodiment according to the invention, the outer surfaces of the extensions are disposed in one plane in the transition portion. Advantageously, the extension is configured as an extension of an inner wall of the adjacent shell or it is configured as an inner wall itself. The extension can be formed at the pump shell, at the turbine shell, or combinations thereof. In an advantageous embodiment, the transition is formed in the radially outer portion, in the radially inner portion of the inner torus, or combinations thereof.

In another embodiment of the invention, the flow cross-section width of the gap is configured to be variable. The flow resistance, e.g., the friction resistance at the defining surface of the gap, should be as large as possible in order to limit the leakage flow through the gap.

In another embodiment according to the invention, the thickness of the extensions varies in the transition portion, which can yield particular gap shapes. Advantageously, a radial extension is formed at least at one extension, which helps to increase the flow resistance in the gap.

BRIEF DESCRIPTION OF THE DRAWINGS

The nature and mode of operation of the present invention will now be more fully described in the following detailed description of the invention in view of the accompanying drawing figures, in which:

FIG. 1a illustrates a cross-section of a hydrodynamic torque converter for an embodiment of the invention between a pump shell and a turbine shell;

FIGS. 1b through 1f illustrate a detail view of area A of FIG. 1a and additional alternative embodiments for the transition;

FIG. 2a illustrates a cross-section through a hydrodynamic torque converter for another embodiment of the invention between the pump shell and the turbine shell; and,

FIGS. 2b through 2f illustrate a detail view of area B of FIG. 2a and additional alternative embodiments of the transition.

DETAILED DESCRIPTION OF THE INVENTION

At the outset, it should be appreciated that like drawing numbers on different drawing views identify identical, or functionally similar, structural elements of the invention. While the present invention is described with respect to what is presently considered to be the preferred aspects, it is to be understood that the invention as claimed is not limited to the disclosed aspects.

Furthermore, it is understood that this invention is not limited to the particular methodology, materials and modifications described and, as such, may, of course, vary. It is also understood that the terminology used herein is for the purpose of describing particular aspects only, and is not intended to limit the scope of the present invention, which is limited only by the appended claims.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood to one of ordinary skill in the art to which this invention belongs. Although any methods, devices or materials similar or equivalent to those described herein can be used in the practice or testing of the invention, the preferred methods, devices, and materials are now described.

FIG. 1a illustrates a cross-sectional view of hydrodynamic torque converter 10 for an embodiment of the invention. Hydrodynamic torque converter 10 includes pump shell 12, turbine shell 14 and stator shell 16, which define in combination a torus-shaped, hydrodynamic flow cycle for a fluid introduced into the converter housing. The effective coupling of the shells configured as pump shell 12, turbine shell 14, and stator shell 16 with the fluid is provided through blades respectively provided at the edges of the shells. The blades are attached to the shells through walls and are supported by the walls. The walls are formed by outer walls 20 and inner walls 18. Inner walls 18 of the shells form inner torus 22. The fluid flows essentially into operating portion 26 defined by the circumferential portion between outer walls 20 and inner walls 18. Since pump shell 12 and turbine shell 14 are rotatable relative to one another and can therefore rotate at different speeds, they are spatially separated from one another through slot 24. The same applies between turbine shell 14 and stator shell 16 and between pump shell 12 and stator shell 16.

Slots 24 interrupt the circumferential extension of inner torus 22 along the torus-shaped flow path of the fluid. Thus, the fluid can leak from operating portion 26 defined circumferentially between outer walls 20 and inner walls 18 into inner portion 28 of inner torus 22 and thus cause flow losses, which can reduce the efficiency of hydrodynamic torque converter 10. In order to reduce the flow losses, hydrodynamic torque converter 10 in this embodiment of the invention includes extension 30 of inner wall 18 at pump shell 12 and extension 32 of inner wall 18 of turbine shell 14 in the radially outer portion of inner torus 22. Ends 36, 38 of extensions 30, 32 overlap in a direction along the torus-shaped flow path and include gap 34 between one another.

FIGS. 1b through 1f illustrate a detail view of area A of FIG. 1a and illustrate additional alternative embodiments of transition 40 between extension 30 of inner wall 18 of pump shell 12 and extension 32 of inner wall 18 of turbine shell 14. In FIG. 1b, transition 40 between extension 30 of inner wall 18 of pump shell 12 and extension 32 of inner wall 18 of adjacent turbine shell 14 is configured to be hydrodynamically smooth. That is, surfaces 44 and 46 are in alignment. Outer surfaces 44, 46 of extensions 30, 32, facing flow path 42 of fluid through the pump, turbine, and stator are thus configured to be smooth in the portion of transition 40, so that flow path 42 is not impeded by any obstruction. Ends 36, 38 of extensions 30, 32 are beveled in a complementary manner, so that the largest defining surface possible is provided for the fluid entering inner portion 28 through gap 34 and thus, as a consequence, the greatest possible friction resistance. Thus, the flow loss through gap 34 towards inner portion 28 of inner torus 22 can be further reduced.

In FIG. 1c, extension 32 of turbine shell 14 includes radial extension 48. End 38 of extension 32 of turbine shell 14 reaches over end 36 of extension 30 of adjacent pump shell 12. The friction resistance for the fluid flowing through gap 34 is increased by radial extension 48 in combination with adjacent end 36 of extension 30 of the pump shell 12. Outer surfaces 44, 46 of extensions 30, 32 are configured to be hydrodynamically smooth.

FIGS. 1d through 1f illustrate additional possible alternatives in which transition 40 with outer surfaces 44, 46 is hydrodynamically smooth and the friction resistance of the flow through gap 34 towards inner portion 28 of inner torus 22 is increased, for example, by configuring the defining surface of the gap 34 as large as possible and the gap dimensions as small as possible. In FIG. 1e, ends 36, 38 of extensions 30, 32 are disposed in plane 50, which means ends 36, 38 do not overlap one another, but are adjacent to one another with respect to plane 50.

FIG. 2a illustrates a cross-sectional view of hydrodynamic torque converter 10 according to another embodiment of the invention. FIGS. 2b through 2f illustrate example embodiments. Pump shell 12 and turbine shell 14 respectively include extensions 30, 32 of inner walls 18 in the radially inner portion of inner torus 22. The extensions are adjacent to one another radially above stator shell 16 and include transition 40. The embodiments shown in FIGS. 2b through 2f are comparable with FIGS. 1b through 1f with the difference that the overlap of walls 18 occurs at the interface of portion 28 with the stator. Thus, the embodiment shown in FIG. 2e illustrates gap 34 with constant flow cross-section width 52, whereas flow cross-section width 52 for the respective embodiments shown in FIGS. 2b, 2d, and 2f varies. In addition, thickness 54 of extensions 30, 32 in portion of transition 40 varies with the distance to extension 32 or 30, respectively, as can be seen in FIG. 2c.

The extension can also be attached at the pump shell and the extension of the inner wall can be attached at the turbine shell. Furthermore, a first shell can include an extension, whereas the second, adjacent shell does not necessarily include an inner wall extension. In this case, the extension of the first shell is adjacent to the inner wall of the adjacent, second shell.

It should be understood that the invention is not limited to the embodiments shown and that combinations of the embodiments shown or combinations of various aspects of the embodiments shown are possible.

Thus, it is seen that the objects of the present invention are efficiently obtained, although modifications and changes to the invention should be readily apparent to those having ordinary skill in the art, which modifications are intended to be within the spirit and scope of the invention as claimed. It also is understood that the foregoing description is illustrative of the present invention and should not be considered as limiting. Therefore, other embodiments of the present invention are possible without departing from the spirit and scope of the present invention.

LIST OF REFERENCE NUMBERS

• 10 hydrodynamic torque converter
• 12 pump shell
• 14 turbine shell
• 16 stator shell
• 18 inner wall
• 20 outer wall
• 22 inner torus
• 24 slot
• 26 operating portion
• 28 inner portion
• 30 extension
• 32 extension
• 34 gap
• 36 end
• 38 end
• 40 transition
• 42 flow path
• 44 outer surface
• 46 outer surface
• 48 radial extension
• 50 plane
• 52 flow cross-section width
• 54 thickness

Claims

1. A hydrodynamic torque converter, comprising:

a pump shell, including a first plurality of blades attached to a first inner wall for the pump shell;

a turbine shell, including a second plurality of blades attached to a second inner wall for the turbine shell; and,

an inner torus partially formed by the first and second inner walls, wherein the first and second inner walls include first and second surfaces, respectively, facing away from the inner torus; the first and second inner walls include first and second ends, respectively; one of the first or second inner walls extends beyond the first or second pluralities of blades, respectively; a gap is formed between the first and second ends; the first and second surfaces are in alignment, at the gap; and, the first and second ends are in alignment with a line orthogonal to an axis of rotation for the torque converter.

2. The hydrodynamic torque converter of claim 1, wherein the first inner wall extends beyond the first plurality of blades.

3. The hydrodynamic torque converter of claim 1, wherein the second inner wall extends beyond the second plurality of blades.

4. The hydrodynamic torque converter of claim 1, wherein the first inner wall extends beyond the first plurality of blades and the second inner wall extends beyond the second plurality of blades.

5. The hydrodynamic torque converter of claim 1, wherein the gap is formed at a radially outer portion of the inner torus.

6. The hydrodynamic torque converter of claim 1, wherein the gap is formed at a radially inner portion of the inner torus.

7. The hydrodynamic torque converter of claim 1, wherein the gap is formed at both a radially outer portion of the inner torus and at a radially inner portion of the inner torus.

8. The hydrodynamic torque converter of claim 1, wherein a flow cross-section width of the gap varies according to a location of the flow cross-section within the gap.

9. The hydrodynamic torque converter of claim 1, wherein a thickness of a portion of the first inner wall varies according to a position of the portion with respect to the gap.

10. The hydrodynamic torque converter of claim 1, wherein a thickness of a portion of the second inner wall varies according to a position of the portion with respect to the gap.

11. The hydrodynamic torque converter of claim 1, wherein a respective radial extension is formed at the first end.

12. The hydrodynamic torque converter of claim 1, wherein a respective radial extension is formed at the second end.

13. A hydrodynamic torque converter, comprising:

a pump shell, including a first plurality of blades attached to a first inner wall for the pump shell;

a turbine shell, including a second plurality of blades attached to a second inner wall for the turbine shell; and,

an inner torus partially formed by the first and second inner walls, wherein the first and second inner walls include first and second surfaces, respectively, facing away from the inner torus; the first and second inner walls include first and second ends, respectively; one of the first or second inner walls extends beyond the first or second pluralities of blades, respectively; a gap is formed between the first and second ends; the first and second surfaces are in alignment, at the gap; and, a line orthogonal to an axis of rotation for the torque converter overlaps the first and second inner walls.

14. The hydrodynamic torque converter of claim 13, wherein the first inner wall extends beyond the first plurality of blades.

15. The hydrodynamic torque converter of claim 13, wherein the second inner wall extends beyond the second plurality of blades.

16. The hydrodynamic torque converter of claim 13, wherein the first inner wall extends beyond the first plurality of blades and the second inner wall extends beyond the second plurality of blades.

17. The hydrodynamic torque converter of claim 13, wherein the gap is formed at a radially outer portion of the inner torus.

18. The hydrodynamic torque converter of claim 13, wherein the gap is formed at a radially inner portion of the inner torus.

19. The hydrodynamic torque converter of claim 13, wherein the gap is formed at both a radially outer portion of the inner torus and at a radially inner portion of the inner torus.

20. The hydrodynamic torque converter of claim 13, wherein a flow cross-section width of the gap varies according to a location of the flow cross-section within the gap.

21. The hydrodynamic torque converter of claim 13, wherein a thickness of a portion of the first inner wall varies according to a position of the portion with respect to the gap.

22. The hydrodynamic torque converter of claim 13, wherein a thickness of a portion of the second inner wall varies according to a position of the portion with respect to the gap.

23. The hydrodynamic torque converter of claim 13, wherein a respective radial extension is formed at the first end.

24. The hydrodynamic torque converter of claim 13, wherein a respective radial extension is formed at the second end.