Abstract:
The present disclosure relates to a torque converter, and more particularly, to a torque converter containing a stator having blades with non-linear edges and non-ruled surfaces to increase fluid flow within the torque converter and improve the performance thereof.

Description:
FIELD OF THE INVENTION 
     The present disclosure relates to a torque converter, and more particularly, to a torque converter containing a stator having non-ruled blades surfaces to reduce fluid losses and improve performance. 
     BACKGROUND OF THE INVENTION 
     A torque converter is a fluid-filed assembly typically used in automatic and powershift transmissions. A torque converter uses fluid to transmit energy from an input, typically an engine, to an output, typically a transmission, and consists of three main components: a turbine, an impeller, and a stator. During the operation of a torque converter, torque generated from the engine drives the impeller. A cover is attached to the impeller so both the cover and impeller rotate at the same speed as the engine. The turbine is connected to an output shaft, and the stator is connected to a non-rotating support shaft. The turbine and impeller have a plurality of blades oriented so that as the impeller rotates, the fluid within the impeller is forced into the blades of the turbine, transmitting energy to the turbine, and forcing it to rotate. The stator has a plurality of blades oriented to direct the fluid leaving the turbine to flow in the direction of the impeller&#39;s rotation rather than in a direction opposing the impeller&#39;s rotation. 
     A thrust washer is a component used within many torque converters to ensure the proper location of the torque converter&#39;s component parts, and is typically located between the impeller and the cover. It is desirable to route fluid through the torque converter to ensure proper functioning. One of the fluid pathways within a torque converter can be around or through the thrust washer. A typical thrust washer contains a multitude of straight grooves on the surface to allow for fluid communication within the torque converter. 
     In a traditional torque converter, the turbine, impeller, and stator are each made up of a plurality of blades having ruled surfaces (or a surface generated by a straight line). As the fluid travels through the channels created by the blades of a traditional torque converter, fluid losses are generated when the fluid flow becomes turbulent. Fluid losses lead to overall performance deterioration and decreased torque converter efficiency. Furthermore, as some automotive designs provide for decreased space for transmission systems, and as automatic transmissions have increased in size over time due to the use of more gears, a need has developed for a torque converter that is smaller in size. Decreasing the overall dimensions of a torque converter decreases the size of the channels created by the blades, further increasing the buildup of fluid losses. Accordingly, there is a need for improvement in the art. 
     SUMMARY OF THE INVENTION 
     The present disclosure broadly comprises a stator designed to allow superior fluid flow and increase overall torque converter efficiency. The stator according to an aspect of the present invention contains a plurality of blades that have non-ruled surfaces. This unique shape of the blades assists in reducing fluid losses by improving the geometry of the channels through which the fluid within the stator flows. 
     The stator blades extend from an inner circumference of the stator to an outer circumference of the stator, and direct the flow of the fluid leaving the turbine output and entering the impeller input. In comparison to traditional stator blade designs that utilize linear edges and ruled-surfaces, the stator blades according to an aspect of the present invention have non-linear leading and trailing edges between the inner circumference and the outer circumference of the stator. Non-linear edges give the stator blades non-ruled surfaces which serve to decrease fluid separation from the blade surfaces. This decreases fluid losses and, in-turn, increases torque converter efficiency by providing an increased fluid flow rate within torque converter. 
     In one embodiment, the leading edge and the trailing edge of the stator blades are contoured such that the stator blades have a convex front surface and concave rear surface. In another embodiment, the leading edge and the trailing edge of the stator blades are contoured such that the stator blades have a concave front surface and convex rear surface. 
     In yet another embodiment, the stator blades are non-linear from the leading edge of the stator blade to the trailing edge of the stator blade. In yet another embodiment, the stator blades have an airfoil shaped cross section. In yet another embodiment, the stator blades have a uniform cross section. 
     The shape of the impeller blades and the turbine blades of a torque converter are defined by the shape of the space in which the impeller and turbine fit within the torque converter. The impeller blades have an outer edge arranged to conform to the inner surface of the torque converter cover, and an inner edge arranged to conform to the outer surface of a torus ring. The turbine blades have a similar shape, with an outer edge arranged to conform to the inner surface of a turbine shell, and an inner edge arranged to conform to the outer surface of the torus ring. The inner edges of the impeller blades are arranged to face the inner edges of the turbine blades such that as the impeller spins, fluid leaving the impeller output enters the turbine input. 
     In yet another embodiment of the present invention, the torque converter contains non-ruled impeller blades and turbine blades usable with the stator of the present invention. In comparison to traditional blade designs that utilize ruled blade surfaces, non-ruled impeller and turbine blades serve to increase the flow rate of the fluid through the channels created by adjacent blades, and therefore further decrease fluid losses within the torque converter. 
     In yet another embodiment of the present invention, the torque converter contains a thrust washer usable with the stator of the present invention, wherein the thrust washer contains at least one groove on its front surface, and the front surface is curved such that the thickness of the thrust washer at the inner diameter is greater then the thickness of the thrust washer at the outer diameter. In comparison to traditional thrust washer designs, the present design increases the length of the at least one groove, allowing for a greater reduction in the velocity of the fluid traveling through the groove which, in turn, lessens fluid turbulence and further increases the fluid flow rate within the torque converter. 
     In yet another embodiment of the present invention, the thrust washer includes at least one groove having a width that is greater at the outer diameter of the thrust washer than at a point proximal to the inner diameter of the thrust washer. This creates a wider entry area to further increase the fluid flow rate within the torque converter. 
     In yet another embodiment of the present invention, the at least one groove of the thrust washer has one side that is substantially straight, and one side that is curved along at least part of a length thereof such that the groove is wider at the outer diameter of the thrust washer than at a point proximal to the inner diameter of the thrust washer. 
     In yet another embodiment of the present invention, the at least one groove of the thrust washer has both sides that are curved along at least part of their length such that the geometry of the curve of the first side in relation to the curve of the second side creates a groove that is wider at the outer diameter of the thrust washer than at a point proximal to the inner diameter of the thrust washer. 
     In yet another embodiment of the present invention, the at least one groove of the thrust washer extends completely from the outer diameter to the inner diameter. 
     In yet another embodiment of the present invention, the thrust washer includes a plurality of grooves arranged radially about the front surface of the thrust washer, and the thrust washer also includes at least one protrusion extending outward from the front surface in proximity to the inner diameter, and between each of the plurality of grooves. 
     Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description, including disclosed embodiments and drawings, are mere exemplary in nature intended for purposes of illustration only and are not intended to limit the scope of the invention, its application or use. Thus, variations that do not depart from the gist of the invention are intended to be within the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross sectional view of a stator in a torque converter according to an embodiment of the present invention; 
         FIG. 2  is a front view of a stator according to an embodiment of the present invention; 
         FIG. 3  is a perspective view of the stator of  FIG. 2 ; 
         FIG. 4  is a perspective view of an impeller according to an embodiment of the present invention; 
         FIG. 5  is a front view of a turbine according to an embodiment of the present invention; 
         FIG. 6  is a perspective view of a thrust washer according to an embodiment of the present invention; 
         FIG. 7  is a side view of the thrust washer of  FIG. 6 ; 
         FIG. 8  is a front view of a second embodiment of a thrust washer according to the present invention; 
         FIG. 9  is a front view of a third embodiment of a thrust washer according to the present invention; 
         FIG. 10  is a perspective view of a fourth embodiment of a thrust washer according to the present invention; and 
         FIG. 11  is a front view of a fifth embodiment of a thrust washer according to the present invention; 
     
    
    
     DESCRIPTION OF THE INVENTION 
       FIG. 1  is a cross sectional view of a torque converter  100  showing the location of an impeller  101 , turbine  102 , stator  103 , cover  104 , torus ring,  105 , and thrust washer  200 . During operation of the torque converter  100 , torque generated from the engine (not shown) drives the impeller  101 . The cover  104  is attached to the impeller  101 , so both the cover  104  and the impeller  101  rotate at the same speed as the engine. The turbine  102  has a plurality of turbine blades  150  and the impeller  101  has a plurality of impeller blades  140  oriented so that as the impeller  101  rotates, the fluid within the impeller  101  is forced out of the impeller  101  into the turbine  102 , transmitting energy to the turbine  102  and forcing it to rotate. The stator  103  has a plurality of stator blades  120  oriented to direct the fluid leaving the turbine  102  into the impeller  101  in the rotational direction of the impeller  101  rather than in a direction opposing the impeller&#39;s rotation. 
       FIGS. 2 and 3  show a stator  103  according to a present embodiment. The stator  103  has a plurality of stator blades  120  extending from an inner circumference  121  to an outer circumference  122  of the stator  103 . Each stator blade  120  has a leading edge  130  and a trailing edge  132 . The leading edge  130  and trailing edge  132  are non-linear from the inner circumference  121  to the outer circumference  122 , thereby creating non-ruled front stator blade surfaces  134  and rear stator blade surfaces  135 . The non-ruled surfaces of the stator blades  120  assist in increasing the fluid flow rate within the channels between the stator blades  120 , which thereby decreases fluid losses and increases torque converter efficiency. These non-ruled stator blade surfaces decrease fluid separation from the stator blade surfaces thus decreasing fluid turbulence and increasing torque converter efficiency. 
       FIG. 4  shows an embodiment of an impeller  101  usable with the stator of the present invention. The impeller  101  has a plurality of impeller blades  140  having a non-ruled surface. In particular, the impeller blades  140  are contoured such that each impeller blade  140  has a non-ruled front impeller blade surface  144  (blade pressure side) and a non-ruled rear impeller blade surface  145  (blade suction side). These non-ruled surfaces serve to further increase the flow rate of the fluid through the channels created by adjacent impeller blades  140 . These non-ruled impeller blade surfaces decrease fluid separation from the impeller blade surfaces thus decreasing fluid turbulence and further increasing torque converter efficiency. 
       FIG. 5  shows an embodiment of a turbine  102  according to the present invention. In this embodiment the turbine  102  has a plurality of turbine blades  150  having a non-ruled surface. In particular, turbine blades  150  are contoured such that each turbine blade  150  has a non-ruled front turbine blade surface  154  and a non-ruled rear turbine blade surface  155 . These non-ruled turbine blade surfaces serve to further increase the flow rate of the fluid through the channels created by adjacent turbine blades  150 , and therefore further decrease fluid losses within the torque converter  100 . These non-ruled turbine blade surfaces decrease fluid separation from the turbine blade surfaces thus decreasing fluid turbulence and further increasing torque converter efficiency. 
       FIGS. 6 and 7  show an embodiment of a thrust washer  200  usable with the stator of the present invention. The thrust washer  200  has an annular body  201  with an outer diameter  202  and an inner diameter  203 . The exemplary thrust washer  200  depicted has a front surface that is curved such that a thickness of the thrust washer  200  is greater at the inner diameter  203  than at the outer diameter  202 . The thrust washer  200  has at least one curved groove  204  located in the front surface of the thrust washer  200 . The groove  204  extends along the curved front surface from the outer diameter  202  towards the inner diameter  203 . The groove  204  follows the curved contour of the front surface of the thrust washer  200  and allows for fluid communication between the inner diameter  203  and the outer diameter  202  when the thrust washer  200  is installed in a torque converter. The exemplary embodiment shown in  FIG. 6  depicts a plurality of spaced apart grooves. The groove(s) route fluid through the torque converter. In one torque converter operating (lock-up) mode, fluid is routed through the groove in a direction from the outer diameter  202  of the thrust washer toward the inner diameter  203 . In another torque converter operating (open converter/cooling) mode, fluid is routed through the groove in a direction from the inner diameter  203  of the thrust washer toward the outer diameter  202 . This design increases the length of groove  204 , allowing for a greater reduction in the velocity of the fluid traveling through groove  204  which, in turn, lessens fluid turbulence and increases the flow rate. The increased flow rate alleviates the buildup of back pressure. 
     As shown in  FIG. 7 , the thrust washer inner diameter thickness (A-A′) is greater than the thrust washer outer diameter thickness (B-B′). As further shown in  FIG. 7 , the inner diameter  203  has a cavity  208  therein configured to connect with the output shaft (not shown). As one of skill in the art would readily understand, the inner diameter cavity can have many different configurations dependant upon the corresponding configuration of the output shaft. 
       FIG. 8  is a front view of a second embodiment of a thrust washer  300  usable with the stator of the present invention. In this embodiment, the grooves  204  have a width that is wider at the outer diameter  202  than at a point proximal  210  to the inner diameter  203  of the thrust washer  300 . In  FIG. 8 , like or corresponding parts are indicated by like reference numerals as used in  FIGS. 6 and 7  and the repeated explanations thereof are omitted. In this second embodiment, the grooves  204  have a first side  305  that is substantially straight at the entry area of the groove  204 , and a second side  306  that is curved along at least a portion of a length thereof. The curvature of the second side  306  creates a groove  204  that is wider at the outer diameter  202  than at a point proximal  210  to the inner diameter  203  of the thrust washer  300 . This creates a wider entry area to further increase the fluid flow rate within the torque converter. 
     Meanwhile, in all of the drawings attached to this specification, like or corresponding parts are indicated by like reference numerals and the repeated explanations thereof are omitted herein. 
       FIG. 9  is a front view of a third embodiment of the thrust washer  400  usable with the stator of the present invention. In this third embodiment, the grooves  204  have both sides curved along at least part of their length. The geometry of the curve of the first side  405  in relation to the curve of the second side  406  creates a groove  204  that is wider at the outer diameter  202  than at a point proximal  210  to the inner diameter  203  of the thrust washer  400 . This creates a wider entry area that increases the fluid flow rate within the torque converter. 
       FIG. 10  is a perspective view of a fourth embodiment of a thrust washer  500  usable with the stator of the present invention. In this fourth embodiment, the grooves  204  extend completely from the outer diameter  202  to the inner diameter  203  of the thrust washer  500 . This design allows for the fluid to pass through the groove  204  at a higher rate, further reducing the buildup of backpressure with the torque converter. 
       FIG. 11  is a front view of a fifth embodiment of a thrust washer  600  usable with the stator of the present invention. In this fifth embodiment, the thrust washer  600  further includes protrusions  207  extending outward from the front surface of the thrust washer  600 . The protrusions  207  are located between adjacent grooves  204  and in proximity to the inner diameter  203  of the thrust washer  600 . The protrusions  207  influence the direction of the fluid within the space between the thrust washer  600  and the cover of the torque converter and therefore further assist in increasing the fluid flow rate within the torque converter. 
     The thrust washer  200  is fabricated from a solid material such as a phenolic, plastic, polyimide resin, or metal. The overall dimensions of the thrust washer  200 , including the size of the inner diameter  203 , outer diameter  202 , and the thickness of the annular body  201 , are not limited except so as to allow for the proper positioning and functioning of the component parts of the torque converter. Furthermore, the depth, width, and quantity of the grooves  204  are not limited and can be selected in any number to allow for an adequate fluid flow rate between the inner diameter  203  and the outer diameter  202  of the thrust washer  100  for desired functioning of the torque converter. 
     It is contemplated that an improved torque converter is provided having a stator as disclosed herein. Further the torque converter can include a non-ruled impeller and/or a turbine with non-ruled blades to further improve fluid flow. Further the torque converter can include an embodiment of the thrust washer as disclosed herein. Of course other combinations of the above torque converter components can be utilized to provide a desirable configuration and performance. Embodiments of the invention disclosed herein provide a torque converter with increased fluid flow capability and otherwise improved fluid flow properties such as reduced fluid turbulence and increased torque converter efficiency.