US3125857A

US3125857A - Hydraulic torque converter

Info

Publication number: US3125857A
Authority: US
Publication date: 1964-03-24
Anticipated expiration: 1981-03-24

Description

March 24, 1964 R. c. SCHNEIDER 3,125,857

HYDRAULIC TORQUE CONVERTER Filed July 11, 1962 4 Sheets-Sheet 1 Me i March 24, 1964 R. c. SCHNEIDER 3,125,857

HYDRAULIC TORQUE CONVERTER Filed July 11, 19 62 4 Sheets-Sheet 2 In de ain! faymond (-fcbfie a'der- March 24, 1964 7 Re. SCHNEIDER 3,125,857

HYDRAULIC TORQUE CONVERTER Filed July 11, 1962 4 Sheets-Sheet 3 msruv EncE 5610 Maui March 1964 R. c. SCHNEIDER HYDRAULIC TORQUE CONVERTER 4 Sheets-Sheet 4 Filed July 11, 1962 United States Patent 3,125,857 HYDRAULHC TGRQUE CGNVERTER Raymond C. Schneider, Rockford, Ill, assignor to Twin Disc Clutch Company, Racine, Wis., a corporation of Wisconsin Filed July 11, 1962, der. No. 269,1397 6 Qlaims. (Cl. 6ll-54-) My invention relates to hydraulic torque converters of the single stage type which are characterized by optimum performance and a type of design enabling economical manufacture.

Gne object of the invention is to provide an hydraulic torque converter in which the attainment of the desired performance is achieved by properly coordinating a number of critical factors including a novel shape of the torus which is provided with continuously curving inner and outer walls, a minimum length of the torus in conjunction with an outflow irnpeller, an inflow turbine and an optimum design of the stator whose blades are very nearly symmetrical with the inner bend of the torus, and a minimum length of the unbladed, outer bend of the torus between the outlet of the impeller and the inlet of the turbine.

A further object is to provide a converter of the character indicated in which the impeller, turbine and stator blades are simply curved between their inlet and outlet tips and are not twisted therebetween whereby in the making of the sand cores preparatory to separately casting the impeller, turbine and stator in one piece, the master blades therefor are draftable and capable of easy removal from the sand core.

In the drawings:

FIG. 1 is a fragmentary, sectional elevation of the improved hydraulic torque converter.

FEGS. 2, 3 and 4 are elevations of the impeller, turbine and stator blades, partly in section and L1 each instance showing a few of the blades, looking in the direction of the arrows 2;, 3 and 4, respectively, in FIG. 1, the several core rings being omitted.

PEG. 5 is a diagrammatic view illustrating the construction for determining the shape of the torus and the blade positions.

FIGS' 6 and 7 show characteristic curves of the converter.

Referring to FIG. 1, the numeral 141 designates the rotating housing of the converter and includes an end wall 11 transverse to the axis of the converter, an axially spaced, impeller wheel ring 12 and an annular wall 13 connecting the wall 11 and ring 12. The end wall 11 is drivenly connected to a source of power (not shown) by a connector 14 to thereby provide for rotation of the impeller wheel ring 12. The latter forms part of an outflow impeller 15 which otherwise includes a core ring 16 axially spaced from the wheel ring 12 and a plurality of impeller blades 17 equispaced around the wheel and

core rings

12 and 16, respectively, and bridged therebetween. As subsequently noted in more detail, the impeller 15, including the component parts above, is formed as a single casting.

The discharge from the impeller 15 enters one end of a reversely curved, unbladed, outer passage 13 whose opposite end connects with the inlet of an inflow turbine 19 which includes a wheel ring 29, an axially spaced, core ring 21, and a plurality of turbine blades 22 equispaced around the wheel and

core rings

21 and 21, respectively, and bridged therebetween. The turbine 19 is also formed as a single casting. The turbine wheel ring 21) has splined connection with a load shaft 23, one end of which may be piloted in a bearing 24 carried by the Wall 11.

Ice

The discharge from the turbine 19 enters one end of a reversely curved, inner passage 25 whose opposite end connects with the inlet of the impeller 15 and the latter passage is for the most part bladed by a stator 26 comprising a wheel ring 27, a core ring 28 spaced therefrom, and a plurality of stator blades 2?! bridged between the wheel and

core rings

27 and 28, respectively. The stator 26 is also formed as a single casting as will be presently described. The stator 26 may be permanently held against rotation by appropriate connection to astationary sleeve 30, or an overrunning clutch 31 may be interposed between the stator 26 and sleeve 30, these alternatives being conventional.

As shown in FIG. 1, the impeller 15, passage 18, turbine 19, passage 25, and the stator 26 are related to form a closed, generally pear or eg -shaped, toroidal path for the working liquid except for an inlet passage 32 in the sleeve 3d and an annular passage 33 included between the sleeve 31) and load shaft 23. The last named passages connect with the toroidal circuit for conventional supply and discharge of cooling oil. Further, the impeller and

turbine blades

17 and 22 are located in the outward and inward flow parts, respectively, of the toroidal circuit, while the stator blades 29 are positioned for nearly axial flow in the reversely curved, inner passage 25.

As shown in FIGS. 2, 3 and 4, the impeller, turbine and

stator blades

17, 22 and 29 are curved, but not twisted, between their inlet and

outlet tips

34 and 3,5, 36 and 37, and 38 and 39, all respectively. Further, referring to FIGS. 1 and 2, the impeller blades 17 are normally related to the wheel and

core rings

12 and 16, respectively, and the wheel ring end 411 of each impeller blade 17' has a greater linear length than that of the core ring end 41 with suflicient foundry approved draft between these ends to. enable the making of a sand core by shell or common sand molding procedures preparatory to casting as hereinafter noted. The same conditions are true with respect to normal positionings of the turbine and

stator blades

22 and 23 relative to their wheel and

core rings

20 and 21, and 27 and 28, all respectively, and with respect to the like length differences of the wheel

andcore ring ends

42 and 43, respectively, of each turbine blade 22, and of the wheel and core ring ends 44 and 45, respectively, of each stator blade 29. The draftable characteristics of the turbine and

stator blades

22 and 29, respectively, are similar to those of the impeller blades 17.

It has heretofore been stated that the toroidal path of the converter is egg or pear-shaped, but this is only a most general reference. Actually, for the performance required and the structural factors desired, the shape of the torus, designated generally by the numeral 4-6 in FIG. 5, is based upon a number of considerations which will now be discussed.

Denoting the outermost radius of the torus 46 from the converter axis 47 by R, basic factors include a construction rectangle 48 whose

short sides

49 and 50 are parallel to and at radii of approximately .95R and .46R, respectively, from the converter axis 47 and whose

long sides

51 and 52 are normal to the converter axis 47 and have an approximate spacing of 36R. The rectangle 48 is in bounding relation to a construction and continuously curving, median design line 53 and indicated sides of the rectangle 48 are tangent to the line 53 in locations presently established. The median design line 53 is partly determined by a number of design points A to J, inclusive, whose series relation is, for convenience, in the direction opposite to the toroidal flow and whose coordinates in relation to the converter axis 47 as the X-axis and a construction base line 54 normal to the axis 47 and extending midway between the

rectangle sides

51 and 52, the base line 54 serving as the Y-axis, are as follows, positive and negative values lying to the right and left, respectively, of the base line 54, as viewed in FIG.

The median design line 53 is further determined by a number of tangents passing through the design points A to J, inclusive, and forming with the converter axis 47 angles having the following approximate values, it being 'noted from FIG. 5 that the

rectangle sides

49, 51, 50

and 52 respectively constitute the tangents passing through the design points A, C, F and I:

Design Points Tangents Angles,

degrees A" 49 0 B- 55 49 C 51 90 D 56 109 E- 57 152 F 50 180 G 58 218 Fr 59 247 I. 52 270 .T 60 313 The design points and tangents listed above having been located, the median design line 53 is drawn through such points in tangential relation to the indicated tangents as an endless line which is characterized by a continuously changing, smooth curvature between each adjacent pair of design points.

The median design line 53 provides a basis for the sizing of the torus 46 since it is employed as the locus of the centers of an infinite number of circles, one of which is identified by the numeral 61 in FIG. 5, and wherein the diameter D of any circle is determined by the following formula:

i 3%)1rR 21r distance of circle center from axis 47 V The quantity R being the outer radius of the torus 46 as stated above.

With a sufficient number of circles 61, it will be apparent that, inner and outer, endless and continuously curving lines can be drawn to all of the circles 61 to define the inner and

outer walls

62 and 63, respectively, of the torus 46. The diameters of the circles 61 vary inversely with the distances of their centers from the converter axis 47 so that, as these distances decrease, the circle diameters increase. The cross-sectional area of the torus 46 normal to the median design line 53 between the inner and

outer walls

62 and 63, respectively, and disregarding the impeller, turbine and

stator blades

17, 22 and 29, respectively, is substantially constant and is equal to approximately 20% of the area of a circle R, the factor R being identified above.

The positionings of the inlet and

outlet tips

34 and 35, 36 and 37, and 38 and 39 of the impeller, turbine and

stator blades

17, 22 and 29, respectively, are controlled by the following considerations. With respect to position, each of these tips includes a design point as designated above and, with respect to inclination relative to the converter axis 47, each of these tips is considered to be a line obtained by the intersection of the surface of a construction cone with the cross section of the torus as viewed in FIG. 5. Angle values of these lines and hence of the blade tips as formed with the converter axis 47 '4 are positive or negative depending upon whether the apex of the associated cone lies to the right or left, or on the impeller or turbine sides, respectively, of the base line 54 in FIG. 5.

For the impeller blades, the inlet and

outlet tips

34 and 35 include design points D and B and form with the converter axis 47 angles of ;-[-3423 and 2725', all respectively. For the turbine blades, the inlet and

outlet tips

36 and 37 include design points I and H and form with the converter axis 47 angles of +2835' and 3453', all respectively. For the stator blades, the inlet and

outlet tips

38 and 39 include design points G and E and form with the converter axis 47 angles of 65 7 and ;+7638', all respectively.

From FIG. 5, it will be apparent that the torus 46 is bladed between design points D and B to form the outflow impeller 15, is further bladed between design points I and H to form the inflow turbine 19, and is further bladed between design points G and E to form the nearly axial iiow stator 26 which may be either fixed in position or conventionally arranged to float by means of the overrunning clutch 31. The portions of the torus between design points B and I, H and G, and E and D, respectively,

are unbladed.

A torus incorporating the above design is characterized by a number of advantages. Provision is made for minimum length of the torus in conjunction with an optimum design of a nearly axial fiow stator, a minimum, unbladed length of the torus between the outlet of the impeller 15 and the inlet of the turbine 19, and a minimum of friction losses under operating conditions. The impeller v is a single casting including the wheel and core rings 12 of any of the blade angles of the finished blades.

Considering the impeller 15, for example, the master blades are mounted on a first mold ring having a curved surface shaped identical with the wheel ring 12 portion of the torus surface 63 (see FIG. 5) and are abutted by p a second mold ring having a curved surface shaped identical with the core ring 16 portion of the torus surface 62. This assembly is then placed in a core box to receive the molding sand, either by Way of shell or common sand molding. When the sand has cured sufficiently, the first mold ring, corresponding in curvature to the impeller Wheel ring 12, and the master blades are moved away from the sand core, the draftability of the master blades permitting this movement. Considering the mold rings related in the manner of the impeller portions of the torus surfaces 62 and 63, the movements of the mold ring forming the impeller portion of the surface 63 and of the master blades would be in a direction away from an imaginary line corresponding to the base line 54 and the movement of the mold ring forming the impeller portion of the surface 62 would be in the opposite direction. The sand core thus formed is placed in the pattern and casting thereafter proceeds in the usual way. The same procedure is employed in the making of a sand core for the turbine 19.

Due to the positions of the stator blades 29, the pro cedure for making the stator sand core is somewhat different. As in the making of the impeller and turbine sand cores, mold rings for determining the curvatures of the stator wheel ring 27 and core ring 28 portions of the torus surfaces 63 and 62, respectively, are provided and master blades shaped identical to the stator blades 29 are appropriately positioned between the mold rings. This assembly is then placed in a core box and the sand is blown and the master blades are individually driven inwardly or towards the axis of the sand core which is afterwards placed in the pattern.

A converter constructed as above provides performance comparable to those having a generally circular toroidal circuit, but without the latters disadvantage of requiring twisted blades. Such blades can only be made by the lost wax or Antioch plaster processes, or by the use of complicated stamping or forming dies. All such variations are relatively expensive compared to the simply curved blades disclosed herein which enable the use of draftable master blades in the preparation of the sand cores.

For optimum performance, the number of impeller blades 17 range from 20 to 28 and their inlet and outlet angles range repectively from 33 to 56 and from to -43 Where zero is defined as being axial in direction, positive is in the same direction as the normal forward rotation of the impeller and negative indicates a direction opposite to the forward rotation. Higher numbers of the impeller blades are related to the lower negative angles, the lower the angle the higher will be the capacity or absorbed torque.

For the turbine 19, the number of blades 22 range from 26 to 32 and the inlet and outlet angles range respectively from |l7.5 and +42, and from 58 to 62. The smaller inlet angles of the turbine blades 22 are related to the smaller negative outlet angles of the impeller blades 17.

For the stator 26, the number of blades 29 range from 22 to 26, preferably 24 blades, whose inlet tangles range between 8 and and outlet angles nange between +58 and +65".

Impeller having 28 to 43 outlet angles are preferably used with turbines having inlet angles ranging between +17.5 and while impellers having outlet angles of 0 to 20 are preferably used with turbines having inlet angles between +38 and +42. Stators having inlet and outlet angles as stated above may be used with any of the mentioned impeller-turbine combinations.

All of the inlet and outlet angles recited above for the several types of blades are measured along the median design line 53, it being known that the angles at the

torus walls

62 and 63 will be different from each other and from the numerically given angles. For example, the inlet and outlet angles of the impeller blades 17 at the wheel ring 12 are 5 to 9 more and 0 to 2 less and the inlet and outlet angles of the blades 17 at the core ring 16 are 4 to 8 less and 0 to 2 more, the inlet and outlet angles of the turbine blades 22 at the wheel ring 20 are 3 to 5 more and 2 to 4 more and the inlet and outlet angles of the blades 22 at the core ring 21 are 3 to 5 less and 2 to 4 less, the inlet and outlet angles of the stator blades 29 at the wheel ring 27 are 4 to 6 less and 3 to 6 more and the inlet and outlet angles of the blades 29 at the core ring 28 are 4 to 6 more and 3 to 6 less than the inlet and outlet angles at the median design line 53 for the impeller, turbine and

stator blades

17, 22 and 29, all respectively.

Further, for best results, the minimum, total flow areas between the blades of the impeller 15, turbine 19 and stator 26 must be related in the following manner and respectively, 11% to 14%, 10.5% to 11%, and 9% to 9.5%, these areas being percentages of the area of a 1rR circle where R is the outside radius of the torus 46.

FIGS. 6 and 7 are performance curves of the improved converter showing, respectively, input and stall torque 6 curves, and typical primary torque and efficiency curves and are self-explanatory.

I claim:

1. An hydraulic torque converter having a generally pear-shaped torus provided with a bladed outflow impeller, a bladed inflow turbine and a substantially axial flow, bladed stator, the portion of the torus between the impeller outlet and turbine inlet being unbladed, the shape of the torus being related by reference to an endless, pearshaped and construction, median design line which is bounded by a construction rectangle whose shorter sides are parallel to. the axis of the converter and tangent to the outermost and innermost points of the design line at approximate distances of .95R and .46R, respectively, from the converter axis and whose longer sides are normal to the converter axis with a spacing of approximately 36R and tangent, respectively, to axially outermost points of the design line wherein R is the outer radius of the torus, the design line passing through a series of design points A to J, inclusive, determined by a system of X- and Y-coordinates beginning with the radially outermost design point A of tangency of the rectangle with the design line and proceeding in succession through the other design points in a direction opposite to that of the toroidal flow, the coordinate system being related to the converter axis and a reference, construction base line perpendicular thereto and passing midway between the longer sides of the rectangle as X- and Y-axes, respectively, the coordinates having values for design point A of OR and .95R, for design point B of |.09R and 91R, for design point C of +.l8R and .63R, for design point D of +.17R and .56R, for design point B of +.10R and .48R, for design point F of OR and .46R, for design point G of .l2R and .50R, for design point H of .17R and .56R, for design point I of .18R and .63R, and for design point I of .09R and .91R, positive and negative values being measured in opposite directions, respectively, from the base line, and the inner and outer walls of the torus being tangent to an infinite number of circles whose centers lie on the median design line with the diameter D of each circle being expressed as follows:

= (20% i 3%)1rR 21r distance of circle center from converter axis 2. An hydraulic torque converter as defined in claim 1 wherein the curvature of the median design line is further determined by a plurality of construction lines each tangent to the median design line at one of the design points A to J, inclusive, respectively, and making angles with the converter axis of 0, 49, 109, 152, 218, 247, 270 and 313.

3. An hydraulic torque converter as defined in claim 2 wherein the impeller, turbine and stator blades are curved and devoid of twist between their inlet and outlet tips and the linear length of each blade at the outer wall of the torus is greater than that at the inner wall, each blade having a casting taper from the outer to the inner wall of the torus.

4. An hydraulic torque converter as defined in claim 3 wherein the cross-sectional area of the torus normal to the median design line and disregarding blade thickness is substantially constant and approximately equal to 20% of the area of a circle of radius R and wherein the minimum, total flow areas between the blades of the impeller, turbine and stator are respectively 11% to 14%, 10.5% to 11% and 9% to 9.5% of the area of a circle of R radius where R is the outer radius of the torus.

5. An hydraulic torque converter as defined in claim 4 wherein the number of impeller, turbine and stator blades respectively range from 20 to 28, 26 to 32 and 22 to 26, and the inlet and outlet angles for the impeller, turbine and stator on the median design line respectively range from 33 to 56 and 0 to 43, +17.5 to +42 and 58 to 62, and '8 to -l5 and +58 and +65 zero degree value being defined as axial in direction, and positive and negative degree values being defined, respectively, as in the same direction as and opposite to the normal direction of impeller rotation.

6. An hydraulic torque converter as defined in claim 3 wherein the inlet and outlet tips of the impeller, turbine and stator are position defined by design points and line intersections of the lateral surfaces of associated construction cones with a cross-sectional plane of the torus which includes the converter axis as follows: for each impeller blade, the lines determining positions of the inlet and outlet tips pass through design points D and B and form with the converter axis angles of +3423 and -2725', for each turbine blade, the lines determining positions of the inlet and outlet tips pass through design points I and H and form with the converter axis angles of 2835 and 3453, for each stator blade, the lines determining positions of the inlet and outlet tips pass through design points G and E and form With the converter axis angles of,65 and-I-7638', all respectively, positive and negative angle values respectively indicating that the apexes of the associated construction cones are located on the impeller and turbine sides of the construction base line.

No references cited.

Claims

1. AN HYDRAULIC TORQUE CONVERTER HAVING A GENERALLY PEAR-SHAPED TORUS PROVIDED WITH A BLADED OUTFLOW IMPELLER, A BLADED INFLOW TURBINE AND A SUBSTANTIALLY AXIAL FLOW, BLADED STATOR, THE PORTION OF THE TORUS BETWEEN THE IMPELLER OUTLET AND TURBINE INLET BEING UNBLADED, THE SHAPE OF THE TORUS BEING RELATED BY REFERENCE TO AN ENDLESS, PEARSHAPED AND CONSTRUCTION, MEDIAN DESIGN LINE WHICH IS BOUNDED BY A CONSTRUCTION RECTANGLE WHOSE SHORTER SIDES ARE PARALLEL TO THE AXIS OF THE CONVERTER AND TANGENT TO THE OUTERMOST AND INNERMOST POINTS OF THE DESIGN LINE AT APPROXIMATE DISTANCES OF .95R AND .46R, RESPECTIVELY, FROM THE CONVERTER AXIS AND WHOSE LONGER SIDES ARE NORMAL TO THE CONVERTER AXIS WITH A SPACING OF APPROXIMATELY .36R AND TANGENT, RESPECTIVELY, TO AXIALLY OUTERMOST POINTS OF THE DESIGN LINE WHEREIN R IS THE OUTER RADIUS OF THE TORUS, THE DESIGN LINE PASSING THROUGH A SERIES OF DESIGN POINTS A TO J, INCLUSIVE, DETERMINED BY A SYSTEM OF XAND Y-COORDINATES BEGINNING WITH THE RADIALLY OUTERMOST DESIGN POINT A OF TANGENCY OF THE RECTANGLE WITH THE DESIGN LINE AND PROCEEDING IN SUCCESSION THROUGH THE OTHER DESIGN POINTS IN A DIRECTION OPPOSITE TO THAT OF THE TOROIDAL FLOW, THE COORDINATE SYSTEM BEING RELATED TO THE CONVERTER AXIS AND A REFERENCE, CONSTRUCTION BASE LINE PERPENDICULAR THERETO AND PASSING MIDWAY BETWEEN THE LONGER SIDES OF THE RECTANGLE AS X- AND Y-AXES, RESPECTIVELY, THE COORDINATES HAVING VALUES FOR DESIGN POINT A OF 0R AND .95R, FOR DESIGN POINT B OF +.09R AND .91R, FOR DESIGN POINT C OF +. 18R AND .63R, FOR DESIGN POINT D OF +.17R AND .56R, FOR DESIGN POINT E OF +10R AND .48R, FOR DESIGN POINT F OF 0R AND .46R, FOR DESIGN POINT G OF -.12R AND .50R, FOR DESIGN POINT H OF -.17R AND .56R, FOR DESIGN POINT I OF -.18R AND .63R, AND FOR DESIGN POINT J OF -.09R, AND .91R, POSITIVE AND NEGATIVE VALUES BEING MEASURED IN OPPOSITE DIRECTIONS, RESPECTIVELY, FROM THE BASE LINE, AND THE INNER AND OUTER WALLS OF THE TORUS BEING TANGENT TO AN INFINITE NUMBER OF CIRCLES WHOSE CENTERS LIE ON THE MEDIAN DESIGN LINE WITH THE DIAMETER D OF EACH CIRCLE BEING EXPRESSED AS FOLLOWS: