Amorphous metal torque convertor stator

A torque convertor stator includes an annular bearing support, a plurality of stator blades, and a web extending radially between the annular bearing support and the plurality of stator blades. The annular bearing support, the plurality of stator blades, and the web are formed from a single continuous piece of amorphous metal.

FIELD OF THE INVENTION

The present subject matter relates generally to torque converter stators.

BACKGROUND OF THE INVENTION

Torque converters generally include an impeller, a turbine and a stator. An engine coupled to the torque converter rotates the impeller to flow fluid within the torque converter from the impeller to the turbine. The flowing fluid from the impeller drives rotation of the turbine, and the turbine is coupled to an input shaft of an associated automatic transmission. Thus, the fluid within the torque converter can hydraulically connect the impeller and the turbine.

After the fluid from the impeller strikes the turbine, the fluid changes direction and recirculates back towards the impeller. Between the turbine and the impeller, the stator redirects the fluid recirculating from the turbine towards the impeller. The stator increases a turbine torque of the torque converter by changing the flow direction of the fluid.

Known stators in torque converter have drawbacks. For instance, certain known torque converter stators are formed from cast aluminum with separate thrust bearings and a one-way clutch outer race pressed into the stator casting. The cast aluminum stator is dimensioned to accommodate press-fitting the separate one-way clutch outer race to the cast aluminum stator resulting in a bulky stator. Separate thrust bearings also require cast-in features on the to cast aluminum stator retain the thrust bearings and stop the thrust bearings from rotating. Separate thrust bearings and races also require distinct sourcing considerations.

BRIEF DESCRIPTION OF THE INVENTION

In example embodiments, a torque convertor stator includes an annular bearing support, a plurality of stator blades, and a web. The web extends radially between the annular bearing support and the plurality of stator blades. The annular bearing support, the plurality of stator blades, and the web are formed from a single continuous piece of amorphous metal.

In a first example aspect, an axial thickness of the web may be no greater than about three millimeters (3 mm) and no less than a half of a millimeter (0.5 mm). In a particular example aspect, the axial thickness of the web may be no greater than about two millimeters (2 mm).

In a second example aspect, a one-way clutch may be positioned at a center opening of the annular bearing support. The annular bearing support may form an outer race of the one-way clutch.

In a third example aspect, the outer race may include a plurality of bearing slots and a plurality of flanges. Each slot of the plurality of bearing slots may be positioned circumferentially between a respective pair of flanges of the plurality of flanges.

In a fourth example aspect, a bearing cap may be mounted to the annular bearing support at the center opening of the annular bearing support.

In a fifth example aspect, the bearing cap may form a first thrust bearing surface.

In a sixth example aspect, the web may form a second thrust bearing surface that faces opposite the first thrust bearing surface of the bearing cap.

In a seventh example aspect, each of the first and second thrust bearing surfaces may define a respective plurality of radial flow channels.

In an eighth example aspect, the one-way clutch may include an inner bearing ring and a plurality of bearings. The inner bearing ring may form an inner race of the one-way clutch. The plurality of bearings may be positioned radially between and ride on the inner and outer races.

In a ninth example aspect, the torque convertor stator may be installed or used within a suitable torque converter.

Each of the example aspects recited above may be combined with one or more of the other example aspects recited above in certain embodiments. For instance, all of the nine example aspects recited above may be combined with one another in some embodiments. As another example, any combination of two, three, four, five, or more of the nine example aspects recited above may be combined in other embodiments. Thus, the example aspects recited above may be utilized in combination with one another in some example embodiments. Alternatively, the example aspects recited above may be individually implemented in other example embodiments. Accordingly, it will be understood that various example embodiments may be realized utilizing the example aspects recited above.

DETAILED DESCRIPTION

Example embodiments of the present disclosure are directed to a torque convertor stator formed from or with an amorphous metal. Utilizing amorphous metal, the torque convertor stator has numerous benefits over known torque convertor stators that are constructed with non-amorphous metal. For example, compared to known cast aluminum torque convertor stators, the torque convertor stator formed from or with amorphous metal may be significantly stronger, harder, and have tighter tolerances. In addition, the torque convertor stator formed from or with amorphous metal may have a decreased axial thickness relative to known cast aluminum torque convertor stators. Thus, a torque convertor that includes the torque convertor stator may advantageously have additional axial space for other components and/or the torque convertor may advantageously have a decreased total axial thickness. As another example, the torque convertor stator formed from or with amorphous metal may be formed with an integrated race for a one-way clutch of the torque convertor stator. Thus, construction of the torque convertor stator may advantageously require fewer parts than known cast aluminum torque convertor stators. As yet another example, a weight of the torque convertor stator formed from or with amorphous metal may be less, e.g., about twenty grams (20 g.), than the weight of known cast aluminum torque convertor stators. As a further example, one or more thrust bearings may be formed on the torque convertor stator. Thus, separate thrust bearings required in known cast aluminum torque convertor stators may be advantageously eliminated.

FIG. 1is a schematic view of a torque converter100according to an example embodiment of the present subject matter. Torque converter100may be used in a suitable vehicle. For example, torque converter100may be installed in a passenger vehicle, such as a car, truck or sport utility vehicle (SUV). As may be seen inFIG. 1, torque converter100may be arranged in power flow between an engine10and an automatic transmission20. Thus, torque converter100may be configured to transmit torque from engine10to automatic transmission20. In particular, engine10may be an internal combustion engine, such as a gasoline or diesel engine, that is coupled to an input102of torque converter100, that may include or correspond to a housing of torque converter100. It will be understood that the internal combustion engine may be connected to input102by a flex plate or similar connection. Torque converter100may transmit the rotation of engine10to an output104of torque converter100, as discussed in greater detail below.

Torque converter100may be used in or with any suitable automatic transmission. For example, automatic transmission10may be constructed or arranged in a similar manner to the automatic transmission described in U.S. Pat. No. 8,398,522 to Bauknecht et al., which is hereby incorporated by reference in its entirety for all purposes.

Torque converter100includes features for hydraulically coupling input102and output104. For example, torque converter100may include a pump or impeller110and a turbine120. Impeller110may be rotationally fixed to input102. Thus, engine10may rotate impeller110by rotating input102. Conversely, turbine120may be rotationally fixed to output104. Thus, rotation of turbine120may also rotate output104.

An interior of torque converter100may be at least partially filled with a fluid F that is flowable between impeller110and turbine120. In particular, engine10may drive rotation of impeller110such that impeller110urges the fluid F against turbine120. As the fluid F from impeller110impacts turbine120within torque converter100, the fluid F drives rotation of turbine120. Because turbine120is coupled to output104, output104may rotate due to the fluid F from impeller110impacting turbine120.

As may be seen from the above, the fluid F within torque converter100may hydraulically couple input102and output104. Such hydraulic coupling may allow power transfer from engine10to automatic transmission20via torque converter100while also allowing relative rotation between impeller110and turbine120and between input102and output104. Thus, e.g., when an associated vehicle is stopped or operating at low speeds, the fluid F within torque converter100may hydraulically couple input102and output104to provide power transfer from engine10to automatic transmission20while also allowing relative rotation between input102and output104to avoid stalling engine10.

Torque converter100may further include a stator200. Stator200may be arranged between turbine120and impeller110. For example, as noted above, the fluid F within torque converter100may be driven from impeller110against turbine120in order to rotate output104. After impacting turbine120, the fluid F returns to impeller110within torque converter100. Stator200deflects the fluid F returning to impeller110from turbine120. By changing the direction of the fluid F between turbine120and impeller110, stator200may increase a torque of turbine120. As may be seen from the above, the fluid F within torque converter100may form a recirculating flow path from impeller110to turbine120, from turbine120to stator200, and from stator200back to impeller110.

As may be seen from the above, lock-up clutch140may mechanically couple input102and output104when lock-up clutch140is closed, and the hydraulic coupling provided by the fluid F may be bypassed. Such mechanical coupling may allow power transfer from engine10to automatic transmission20without relative rotation between input102and output104or with negligible relative rotation between input102and output104, e.g., due to slipping between the plates of lock-up clutch140. Thus, e.g., when an associated vehicle is operating at high speeds, lock-up clutch140may close for mechanical coupling between input102and output104and to provide more efficient power transfer from engine10to automatic transmission20.

Torque converter100may also include a torsion damper150. Torsion damper150is disposed in the, e.g., hydraulic and/or mechanical, power flow between input102and output104. Torsion damper150is configured to attenuate rotary oscillations of engine10from being transferred into automatic transmission20through torque converter100. Torque converter100may include one or more series of coil springs, one or more sets of moving masses, and combinations thereof (indicated generally with152) that temporarily store energy occurring in rotational irregularities of engine10and then guide such energy into automatic transmission20with a smoother speed characteristic and/or torque characteristic. As an example, torsion damper150may include turbine torsional vibration dampers, two-damper converters, mass pendulums, etc. Thus, torsion damper150may assist with attenuating engine rotary oscillations to improve shift quality in automatic transmission20and/or improve acoustic properties relative to torque converters without torsion dampers.

Torque converter100may further include a freewheel or one-way clutch240. One-way clutch240may be configured to allow stator200to rotate in a first rotational direction, e.g., that corresponds to the rotational direction of engine10and input102, and may block rotation of stator200in a second, opposite rotational direction. For example, during operation of torque converter100, a rotation speed of output104may increase and approach a rotation speed of input102. In such conditions, stator200may rotate freely in the first rotational direction in the current of the fluid F on one-way clutch240. Thus, torque converter100may act as a “pure” fluid clutch without torque multiplication from stator200. An inner race244of one-way clutch240may be fixed to a housing22, e.g., of automatic transmission20.

FIG. 2is a partial, section view of certain components of torque converter100including stator200.FIG. 3is a front, perspective view of stator200.FIG. 4is a side, section view of stator200.FIG. 5is a rear, perspective view of stator200. As discussed in greater detail below, stator200has various benefits over known torque converter stators. For example, stator200may be significantly stronger, harder, thinner, and have tighter tolerances and/or fewer components than known torque converter stators. Stator200may define an axial direction A, a radial direction R, and a circumferential direction C.

As shown inFIGS. 2 through 5, stator200may include an annular bearing support210. Annular bearing support210may support various components of stator200, including one-way clutch240. For example, annular bearing support210may define a center opening212. One-way clutch240may be disposed at center opening212of annular bearing support210. Annular bearing support210may have a generally circular cross-section shape, e.g., in a plane that is perpendicular to the axial direction A. However, various features of one-way clutch240may be formed on an inner surface214of annular bearing support210, e.g., that faces center opening212. Thus, e.g., it will be understood that the cross-sectional shape of annular bearing support210need not be perfectly circular in various example embodiments.

A bearing cap250may be mounted to annular bearing support210at center opening212. Bearing cap250may assist with mounting one-way clutch240to annular bearing support210. For example, one-way clutch240may be positioned between bearing cap250and a flange216of annular bearing support210, e.g., along the axial direction A. Flange216may extend inwardly along the radial direction R from annular bearing support210, and flange216may be positioned opposite bearing cap250about one-way clutch240, e.g., along the axial direction A. Various components of one-way clutch240, e.g., an inner bearing ring247, rollers/bearings248, etc., may be held between flange216and bearing cap250on annular bearing support210. Flange216may also be positioned at a side of annular bearing support210that is adjacent to a side of web230that forms a second thrust bearing surface232, which is described in greater detail below.

Stator200may also include a plurality of stator blades220. Stator blades220may be shaped to deflect and reorient the fluid F returning to impeller110from turbine120, as noted above. Stator blades220may extend along the radial direction R, e.g., from an inner ring support222to an outer ring support224. Stator blades220may also be distributed, e.g., uniformly, along the circumferential direction C. Stator blades220may include no less than ten (10) stator blades, no less than twenty (20) stator blades, etc. in various example embodiments.

Stator200may further include a web230. Web230may extend, e.g., along the radial direction R, between annular bearing support210and stator blades220. Thus, web230may connect or couple annular bearing support210and stator blades220. In particular, web230may connect or couple annular bearing support210and stator blades220such that stator blades220are rotationally fixed relative to annular bearing support210.

Various components of stator200may formed from or with amorphous metal or metallic glass. Amorphous metal may be a solid metallic material with disordered atomic-scale structure. For instance, the atomic-scale structure may be non-crystalline. In certain example embodiments, the amorphous metal may include various alloys that include zirconium, copper, nickel, and other metals. For example, the amorphous metal may be one or more of: an alloy of zirconium, copper, nickel, titanium, and beryllium; an alloy of zirconium, copper, nickel, aluminum, and titanium; an alloy of zirconium, copper, nickel, and aluminum; and an alloy of zirconium, copper, nickel, aluminum, and niobium. Alternatively, the amorphous metal may be a steel alloy or a magnesium alloy. The amorphous metal may be melted and injection molded to form stator200. By injection molding components of stator200with amorphous metal, high volumes of stator200may be advantageously manufactured cost effectively. Stator200may be formed by an additive manufacturing process or other suitable manufacturing method in alternative example embodiments.

As noted above, various components of stator200may formed from or with amorphous metal. In particular, annular bearing support210, stator blades220, and web230may be formed from a single continuous piece of amorphous metal. Thus, e.g., annular bearing support210, stator blades220, and web230may be formed in a single step amorphous metal injection molding process. After injection molding annular bearing support210, stator blades220, and web230from amorphous metal, post-processing, e.g., machining, of such components may also be advantageously eliminated or reduced relative to known cast aluminum torque convertor stators. For instance, the single continuous piece of amorphous metal that forms support210, stator blades220, and web230may require no additional post-processing, e.g., other than removing gates and runners.

By forming stator200from amorphous metal, stator200may be significantly stronger, harder, and have tighter tolerances than known cast aluminum torque converter stators. For example, known cast aluminum torque converter stators have a tolerance no less than two tenths of a millimeter (±0.2 mm), and an injection molded amorphous metal stator may have a tolerance of no less than two hundredths of a millimeter (±0.02 mm). Due to tolerance increases, a size of stator200may be reduced relative to known torque convertor stators that utilize traditional fabrication techniques. As another example, by forming stator200from amorphous metal, stator blades220have a critical dimension tolerance of one percent (1%), a significant improvement over the critical dimension tolerance of ten percent (10%) provided by traditional fabrication techniques. The critical dimension of the stator blades220may correspond to a spacing between adjacent stator blades220, a length of stator blades220between leading and trailing edges of stator blades220, etc.

In addition, as shown inFIG. 4, a thickness T of web230, e.g., along the axial direction A, may be less than the thickness of known injection molded stators. For example, the thickness T of web230may be no greater than about three millimeters (3 mm) and no less than a half of a millimeter (0.5 mm). As another example, the thickness T of web230may be about two millimeters (2 mm). As used herein, the term “about” means within a quarter of a millimeter (0.25 mm) of the stated width when used in the context of widths. Such recited thicknesses T are significantly less than the thicknesses in known cast aluminum torque convertor stators. The space and/or weight savings provides by such reduced axial thicknesses may advantageously be occupied by other torque converter components, transmission components, etc.

The thickness T of web230may vary along the radial direction R. For example, the thickness T of web230may taper from adjacent annular bearing support210to adjacent stator blades220. Alternatively, the thickness T of web230may be constant along the radial direction R.

FIG. 6is another front, perspective view of stator200with bearing cap250of stator200removed. As shown inFIG. 6, annular bearing support210may form an outer race242of one-way clutch240, e.g., at inner surface214of annular bearing support210. Thus, at least a portion of one-way clutch240may be formed with or integrated into annular bearing support210. In certain example embodiments, outer race242may be a cylindrical surface. Alternatively, as shown inFIG. 6, outer race242may include a plurality of bearing slots244and a plurality of walls or flanges246.

Each slot244may be positioned between a respective pair of flanges246, e.g., along the circumferential direction C. A bearing248, such as a cylindrical steel bearing or roller, may be disposed within each respective bearing slot244. Slots244may be shaped to engage bearings248and provide the one-way functionality of one-way clutch240described above.

Flanges246may contain or hold bearings248within slots244. Flanges246may extend inwardly, e.g., along the radial direction R, from annular bearing support210towards center opening212. Flanges246may be formed of or with the single continuous piece of amorphous metal that forms annular bearing support210, stator blades220, and web230. In certain example embodiments, bearing slots244may include no less than five (5) bearing slots, and flanges246may include no less than five (5) flanges.

By forming outer race242of one-way clutch240with annular bearing support210, a total number of components for stator200may be advantageously reduced. For example, known cast aluminum torque convertor stators require separate, e.g., steel, outer races that are separately manufactured and press-fit on the cast aluminum torque convertor stators. Thus, the separate manufacturing process and associated tolerance stack for outer races may be advantageously eliminated by forming outer race242of one-way clutch240with annular bearing support210. In addition, in known cast aluminum torque convertor stators, significant forces are applied to the cast aluminum torque convertor stators in order to mount the separate outer races. To account for such forces, the webs in known cast aluminum torque convertor stators have a significant axial thickness. Because a separate outer race is not press-fit to the annular bearing support, the thicknesses T of web230may be advantageously reduced compared to known cast aluminum torque convertor stators.

Turning back toFIGS. 2 and 4, one-way clutch240may also include an inner bearing ring247and bearings248, such as cylindrical or ball bearings. Inner bearing ring247may form an inner race249of one-way clutch240. Bearings248may be positioned between inner and outer races242,249and may ride on inner and outer races242,249. Inner race249may complement outer race242. For example, inner race249may be cylindrical. In alternative example embodiments, inner race249may include bearing pockets and flanges as discussed above for outer race242. Inner bearing ring247may, e.g., be formed of steel or another suitable metal.

FIG. 7is a front, perspective view of bearing cap250of stator200.FIG. 8is a rear, elevation view of bearing cap250.FIG. 9is a front, elevation view of bearing cap250. As shown inFIGS. 2-4, bearing cap250may be mounted to annular bearing support210at center opening212of annular bearing support210. Turning back toFIGS. 7-9, bearing cap250may have a first side256and a second side258. First and second sides256,258of bearing cap250may be positioned opposite each other on bearing cap250, e.g., along the axial direction A.

Bearing cap250may form a first thrust bearing surface252, e.g., at first side256of bearing cap250. Thus, bearing cap250may form an integral thrust bearing on a surface of bearing cap250. First thrust bearing surface252of bearing cap250may contact and slide against another component of torque converter100, such as a plate154of torsion damper150, as shown inFIG. 2. Thus, force may be transferred between plate154and stator200via the interface formed with first thrust bearing surface252.

With reference toFIGS. 4-6, web230may form a second thrust bearing surface232. Thus, web230may form an integral thrust bearing on a surface of web230. Second thrust bearing surface232of web230may contact and slide against another component of torque converter100, such as housing102of torque converter100, as shown inFIG. 2. Thus, force may be transferred between housing102and stator200via the interface formed with second thrust bearing surface232. Second thrust bearing surface232may face opposite first thrust bearing surface252, e.g., along the axial direction A.

Each of first and second thrust bearing surfaces252,232may include a respective plurality of channels254,234. Channels254may extend across first thrust bearing surface252, e.g., along the radial direction R. Similarly, flow channels234may extend across second thrust bearing surface232, e.g., along the radial direction R. Fluid F may flow through channels254, e.g., to assist with cooling the thrust bearings, reducing friction, etc.

Bearing cap250may also include a plurality of channels259at second side258of bearing cap250. Channels259may extend across second side258of bearing cap250, e.g., along the radial direction R. Fluid F may flow through channels259, e.g., to assist with cooling the bearings258, reducing friction, etc.