DESC:FORM 2

THE PATENTS ACT, 1970
(39 of 1970)
&
THE PATENT RULES, 2003

COMPLETE SPECIFICATION
(See Section 10 and Rule 13)

Title of invention:
HYDRAULIC TORQUE CONVERTER ASSEMBLY

Applicant:
BEML Limited
A company Incorporated in India under the Companies Act, 1956
Having address:
BEML Soudha, 23/1, 4th Main,
Sampangirama Nagar, Bengaluru - 560 027,
Karnataka, India

The following specification particularly describes the invention and the manner in which it is to be performed.
CROSS-REFERENCE TO RELATED APPLICATIONS AND PRIORITY

The present invention claims priority from Indian patent Provisional Application 202041007536 filed on 21 February 2020.
TECHNICAL FIELD
The present subject matter described herein, relates hydraulic torque converter with lockup clutch design. More particularly squash type hydraulic torque converter.
BACKGROUND
The torque transfer mechanism of vehicles performed by torque converter with an automatic transmission. It provides infinite variable torque ratio to overall power train unit. Conventionally, hydraulic torque converter in automotive equipment have been designed in circular torus shapes to ensure smooth circulation of fluid and confirm the efficient hydrodynamic torque transfer between impeller and turbine. However, the torque converter elements associated with these vehicles are complex in nature due to three dimensional blade curvatures and inhabits additional width. The round type torque converter requires separate clutch units for locking the stator for torque converter mode and locking the turbine with engine speed for lockup mode operations.
The maximum amount of torque multiplication produced by a converter is highly dependent on the size and geometry of the impeller, turbine and stator blades. Generally, the round type converter having the blades with three dimensional curvatures which requires additional man-hours in setting the cores for the number of blades.
Hence, there is necessity of compact size torque converter to achieve high efficiency, high torque capacity and to perform smooth operations.
SUMMARY
Before the present assembly is described, it is to be understood that this application is not limited to the particular machine or an apparatus, and methodologies described, as there can be multiple possible embodiments that are not expressly illustrated in the present disclosures. It is also to be understood that the terminology used in the description is for the purpose of describing the particular versions or embodiments only, and is not intended to limit the scope of the present application. This summary is provided to introduce aspects related squash type hydraulic torque converter with lockup clutch design The aspects are further elaborated as below in the detailed description. This summary is not intended to identify essential features of the proposed subject matter nor is it intended for use in determining or limiting the scope of the proposed subject matter.
The present subject matter described herein, in general, relates to a squash type hydraulic torque converter with lockup clutch.
In order to reach above-mentioned purpose of the present invention introduced guide as rotating member combined with impeller to improve the efficiency and reduces the secondary flow losses. The optimum clearance achieved in between lockup friction discs and lockup pressure plates during disengagement, which minimizes the drag torque and ensures smooth engagement. The present subject matter allows squashed ratio lower than or equal to overall width (W) in axial direction divided by an extreme flow path diameter (D) in radial direction and it results into equivalent or greater efficiency along with required torque capacity in-line with round type converter. A one-way clutch freewheel assembly introduced in order to automatically allowed the stator rotation as per low load demand conditions.
The invention adopted in automatic power-shift transmission and may be used in constructions or off-highway equipment.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing detailed description of embodiments is better understood when read in conjunction with the appended drawings. For the purpose of illustrating the present subject matter, an example of construction of the present subject matter is provided as figures; however, the present subject matter is not limited to the specific process and system disclosed in the document and the figures.
The present subject matter is described in detail with reference to the accompanying figures. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the drawings to refer various features of the present subject matter.
Figure 1 illustrates the vehicle power train flow arrangements with squash type hydraulic torque converter, in accordance with the present invention.
Figure 2 illustrates a squash type hydraulic torque converter assembly, in accordance with the present invention.
Figure 3 illustrates a squash type hydraulic torque converter assembly isometric view, in accordance with the present invention.
Figure 4 illustrates the torque converter hydraulic flow diagram, in accordance with the present invention.
Figure 5 illustrates squash type torque converter design parameters, in accordance with the present invention.
Figure 6 illustrates small elliptical dimensional details (squash ratio), in accordance with the present invention.
Figure 7 illustrates the lockup clutch assembly with optimum clearance between lockup friction discs and lockup pressure plates.
Figure 8 illustrates the blade geometry and angle measurement details of hydraulic torque converter elements, in accordance with the present invention.
Figure 9 illustrates the blade pitch to chord relationship of hydraulic torque converter elements, in accordance with the present invention.
Figure 10 illustrates the internal pressure established inside the elliptical torus portion of hydraulic torque converter elements, in accordance with the present invention.
Figure 11 illustrates the sub-assembly of each torque converter elements used for fluid flow model generation and casting contour blade profiles with isometric view, in accordance with the present invention.
Figure 12 illustrates computational fluid dynamic analysis for torque converter elements along with guide rotation, in accordance with the present invention.
Figure 13 and 14 illustrates stabilized residual and torque monitoring plots in computational fluid dynamic analysis for stall condition, in accordance with the present invention.
Figure 15 illustrates the performance characteristics details with flat torque capacity curve at lower speed ratios in improved squash type torque converter assembly, in accordance with the present invention.
Figure 16 illustrates the torque converter absorption characteristics curves at different speed ratio conditions, in accordance with the present invention.
DETAILED DESCRIPTION
Some embodiments of this disclosure, illustrating all its features, may now be discussed in detail. The words "comprising," "having," "containing," and "including," and other forms thereof, are intended to be equivalent in meaning and be open ended in that an item or items following any one of these words is not meant to be an exhaustive listing of such item or items, or meant to be limited to only the listed item or items. It must also be noted that as used herein and in the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Although any assembly and methods similar or equivalent to those described herein can be used in the practice or testing of embodiments of the present disclosure, the exemplary, assembly and methods are now described. The disclosed embodiments are merely examples of the disclosure, which may be embodied in various forms.
As used in the present invention, the following terms are generally intended to have the meaning as set forth below, except to the extent that the context in which they are used indicate otherwise.
Torque ratio - Refers to the ratio between turbine torque to impeller torque.
Speed Ratio - Refers to the ratio between turbine speed to impeller speed.
Efficiency- Refers to the product of torque ratio and speed ratio.
Capacity Factor - Refers to the absorption characteristics of torque converter in-terms of torque capacity.
Various modifications to the embodiment may be readily apparent to those skilled in the art, and the generic principles herein may be applied to other embodiments of a squash type hydraulic torque converter with lockup clutch design for road equipment. However, one of ordinary skill in the art may readily recognize that the present disclosure for a squash type hydraulic torque converter with lockup clutch design for road equipment is not intended to be limited to the embodiments described, but is to be accorded the broadest scope consistent with the principles and features described herein.
Referring now to Figure 1, wherein the vehicle power train flow arrangements are shown. The power from an engine (102) is transmitted through the hydraulic oil by a torque converter (101) to a transmission unit (104), a differential unit (105) and a rear axle (106) through a wheel in agreement with change in load. The hydraulic torque converter (101) protects the transmission unit (104) by absorbing rotational irregularities generated during engine combustion. The hydraulic torque converter (101) also protects the engine (102) by absorbing abrupt variation of load. The torque converter (101) is configured with an engine driven power take off (PTO) (103) to provide inputs.
Now referring to Figure 2, the figure illustrates the assembly of squash type hydraulic torque converter (101) configured with the engine (102) as a prime mover having a crankshaft, a flywheel and a damper unit coupled through an input coupling (7), a drive shaft (8), a housing (9), a ring gear (10), a drive case (11) and an impeller (3). The impeller (3) comprises plurality of impeller blades (3C) extending from shell (3A) to core (3B) portion of the impeller (3). A guide (15) is coupled with impeller (3) along with a retainer (24). A turbine (4) is the output member configured to a transmission input shaft (25) by an output drive unit (16). The housing (9) and the output drive unit (16) is supported by a radial bearing (34). A turbine (4) comprises plurality of a turbine blade (4C) extending from a shell (4A) to a core (4B) portion of the turbine (4). A stator (5) configured in-between the impeller (3) and the turbine (4). The stator (5) comprises plurality of a stator blade (5C) extending from a shell (5A) to a core (5B) portion of a stator (5). A race (6) is configured to the stator (5) and an one-way clutch (22A) configured in a spacer (22) side outside diameter to the race (6) side inner diameter. A heat resistance bush RH (20) and a bush LH (19) assembled along with the spacer (22), wherein the heat resistance material may brass type. The spacer (22) is locked with a hollow shaft (17) through the spline connection. The hollow shaft (17) sub-assembly comprises a four-point contact ball bearing (18) with a lock-nut (21). To avoid the slippage and switch over from the torque converter mode to lockup mode, the lockup clutch assembly comprises plurality of a lockup friction disc (13) and a lockup pressure plates (12) is connected by using a ring gear (10) and the output drive unit (16). An oil from a lockup control valve (310) is passed through a filter element (31) to the lockup clutch assembly. The entire torque converter assembly is enclosed with a rear case (1) and a front case (2). The front case (2) and a drive shaft (8) is supported by a radial roller bearing (27). A retainer (26) is configured with a front case (2) to a mount oil seal (30) and locking support to a radial roller bearing (27). The torque converter (101) is configured with power take-off unit (103) in order to provide different power tapping to run the hydraulic pump with different power ratings. The drive shaft (8) is mesh with an idler gear (23) with double row taper an outer type bearing (29) with a lock-nut (28). A torque converter control valve (32) is configured with a valve plate assembly (33).
Now referring to Figure 3, the Figure 3 illustrates the squash type hydraulic torque converter assembly isometric view (301) with all sub-assembly details.
Referring now to Figure 4, the Figure 4 illustrates a hydraulic torque converter oil flow (401). The torque converter oil from oil pan is circulating by a gear pump through main filter used to absorb the contaminated particle from the gear pump and circulated to the torque converter control valve (32). The torque converter valve (32) consists of a main relief valve and a torque converter relief valve in order to maintain the required pressure inside the torque converter assembly. The torque converter inlet oil pressure P1 (8~9 bar) is maintained by the torque converter relief valve and the oil gets entered inside the elliptical torus portion with the help of oil passage provided in the rear case (1), the hollow shaft (17) and the guide (15). The outlet oil pressure P2 (3~4 bar) is maintained with the help of torque converter regulator valve which is assembled at rear case (1). The oil exit from the torque converter outlet passage is circulating through the inlet portion of an oil cooler. Thereafter, the cooled oil is recirculated to the transmission (104) and the Power Take Off (103) components for lubrication, wherein the lubrication pressure (0.5~2 bar) is maintained by the lubrication valve. During normal load condition, the lockup clutch assembly gets energized by using the lockup control valve (310). The oil enters from main hydraulic passage to the lockup clutch assembly by the rear case (1), the hollow shaft (17) and the transmission input shaft (25).
In another embodiment, the guide with the effective curvature radius (15) is introduced as rotating member combined with the Impeller (3) in order to improve the efficiency and reduce the secondary flow losses.
In one embodiment, the improved squash type hydraulic torque converter assembly (101) with lockup clutch having equivalent efficiency and torque capacity compared with conventional round type torque converter is disclosed. The improved squash type hydraulic torque converter reduces the axial length around 30 to 35 percent comparatively and ensures smooth flow transfer and thereby confirming the hydrodynamic torque transfer. The gap between the impeller blade (3C) and the turbine blade (4C) flow area (510), the gap between the turbine blade (4C) and the stator blade (5C) flow area (520) and the gap between the stator blade (5C) and the impeller blade (3C) flow area (530) is optimized based on computational fluid dynamic analysis.
Referring to Figure 5, The Figure 5 illustrated the gap and radius details, wherein the impeller exit radius is R1, the impeller entry radius is R2 and the turbine exit radius is R3. The gap between the Impeller blade (3C) and the turbine blade (4C) flow area (510) is achieved, and it ranges 0.13 to 0.15 times of overall flow area. Further, the gap between turbine blade (4C) and the stator blade (5C) flow area (520) is achieved, and it ranges 0.014 to 0.016 times of overall flow area. Similarly, the gap between stator blade (5C) and the impeller blade (3C) flow area (530) is achieved, and it ranges of 0.35 to 0.37 times of overall flow area.
In another exemplary embodiment, a squashed ratio (601) lower than or equal to 0.22 which is overall width (W) in axial direction divided by an extreme flow path diameter (D) in radial direction. The Figure 6 illustrates the elliptical dimensional details (Squash ratio) of hydraulic torque converter assembly.
Referring now to Figure 7, the figure illustrates a lockup clutch assembly (610) with optimum clearance between the lockup friction discs (13) and the lockup pressure plates (12). During disengagement operation of the lockup clutch assembly (610), the lockup clutch control valve may restrict the flow of fluid to the lockup wet multi-plate clutch assembly. Subsequently, a piston (14) may release pressure on the wet multi-plate lockup clutch assembly (610) by torque converter internal pressure. Further, the pressure plate (12) may move in the direction away from the friction discs (13). Due to aforesaid movement of the pressure plate (12), each of the friction discs (13) may disengage from the adjacent pressure plates (12). Further, due to predefined clearance (Ø) in the range of 0.55 to 0.65 between the friction discs (13) and the pressure plate (12), the viscous drag torque is substantially reducing during disengagement of the lockup clutch assembly (610). The conditions of the lockup clutch engagement ensure at 0.7 to 0.8 speed ratio by using the lockup control valve assembly (310) configured with the one-way clutch (22A) mechanism. The stator blades (5C) are designed accordingly, therefore the oil hits the upper side near to the nose radius of the entry portion and thereby the stator (5) allows to rotate in same direction of the impeller (3) rotation. Thus, coupling point ensured for low load demand condition.
Figure 8 illustrates the blade geometry and an angle measurement detail (701) for the impeller (3), the turbine (4) and the stator (5). The blade design of the hydraulic torque converter transfers all the torque. The torque converter blade assembly for the impeller (3), the turbine (4) and the stator (5) require to receive fluid with minimal shock losses. The impeller blades (3C) are to impart energy of the fluid. The impeller blade angle keenly deciding the performance characteristics such as stall torque ratio and torque absorption capacity. The turbine (4) obtains fluid from the impeller (3) and captivates the energy by refracting the fluid and discharging towards the back direction. Similarly, the stator (5) obtains the backward direction discharge from the turbine (4) and deflects it to a forward direction and thereby increases the momentum of the fluid entering to the impeller (3) with minimal flow losses. Therefore, the assembly achieves the optimum entry and exit angle for all the elements for higher torque converter efficiency with optimum capacity factor.
Further, referring to Figure 8, the impeller element blade (3C) entry and exit angle is in the range of 56~57° and 121~122° respectively. In turbine the element blade’s (4C) entry and exit angle is in the range of 128~129° and 26~27° respectively. In the stator element blade’s (5C) entry and exit angle is in the range of 108~109° and 36~37° respectively.
Referring to Figure 9, wherein the pitch to chord relationship of a torque converter element (801) is illustrated. The spacing between each adjacent blades is known as pitch and pitch is always considered at the outer diameter of the blade design path. Chord is considered as the radial distance between the blade inlet and exit on the design path. An impeller pitch (P) to the chord (C) ratio (810) maintained in the range of 0.56 to 0.58, a turbine pitch (P) to the chord (C) ratio (820) maintained in the range of 0.66 to 0.68 and a stator pitch (P) to the chord (C) ratio (830) maintained in the range of 0.97 to 0.99. Aforesaid ratios are derived to achieve the maximum efficiency with optimum blade spacing and considering a capacity factor.
Referring to Figure 10, wherein the figure 10 illustrates the internal pressure (P) established inside an elliptical torus portion (901) and it depends on torque converter inlet and outlet pressure range.
In an exemplary embodiment, internal pressure established in the range of 6 to 7 bar for obtaining the maximum torque converter efficiency with optimum capacity factor.
Figure 11 illustrates sub-assembly of each torque converter elements used for flow model generation and isometric representation of casting a contour blade profiles (920).
In an exemplary embodiment, an impeller blades isometric view (930) stated around 25 numbers of blades. Furthermore, an impeller sub-assembly (935) consists of the impeller (3) configured with casting blades which is merged with shell and core portions and also the guide (15) is assembled along with retainer (24) as rotating member with the engine (102) input speed. A turbine blades isometric view (945) stated around 40 numbers of blades and turbine (4) is configured with casting blades, which is merged with shell and core portions. A stator blades isometric view (960) stated around 47 numbers of blades and a stator sub-assembly (965) consists of the stator (4) configured with casting blades which is merged with shell and core portions along with the race (6). Based on aforesaid sub-assemblies of the impeller, the turbine and the stator fluid flow models (940, 955 & 970) are generated for Computational Fluid Dynamic (CFD) analysis and torque converter performance characteristics are analyzed.
Figure 12 illustrates the computational fluid dynamic analysis by considering the impeller (3) with the guide (15) rotation. Numerical settings in the internal flow fields are the space in flow passage with full of fluid.
In an exemplary embodiment, the virtual model of the hydraulic torque converter involves the torque converter assembly model and the circulating three dimensional fluid flow models. The model may utilize 3D-CAD model software, blade surface contour, the internal surface contour of shell and core have extracted from a torque converter model in order to form a fluid flow passage shape, wherein the fluid flow model is interrelated with the torque converter model. The flow field numerical calculations are achieved by using Computational fluid dynamics (CFD) software. Three dimensional, steady and transient state condition, in-compressible fluid flow with C4 SAE30 oil, Reynolds Averaged Navier Stokes (RANS) equation with realizable k-? turbulence model and Moving Reference Frame (MRF) options are enabled for fluid flow simulation. In the model the impeller (3) velocity remains constant and the turbine (4) speed changes with the different speed ratio conditions. The stator (5) speed remains zero at different speed ratio until coupling point reaches. The flow occurs at different speed ratio conditions with the help of constant impeller with guide rotation and variable turbine rotation as per speed ratio. The flow also redirected from the stator (5) exit angle portion to the impeller suction side for carry over the momentum in-terms of torque and speed variation. As per the analysis, a velocity magnitude is peak at exit angle portion of impeller (3) and entry angle portion of turbine (4). The velocity decreases gradually from core to shell surface of torque converter elements. The severe non-uniform flow angle distribution causes high flow losses in the impeller (3) flow passage. An uniform flow angle distribution ensures to reduce the flow losses. Further, the Computational Fluid Dynamic Analysis ensures cavitation free fluid flow inside the squashed torus portion by eliminating the negative pressure.
Figure 13 & 14 illustrates stabilized residual and torque monitoring plots of torque converter elements in computational fluid dynamic analysis for stall condition. In stall condition, the turbine (4) is not allowed to rotate, whereas the impeller (3) is allowed to lock at maximum speed condition. The residual and torque monitoring is one of the most important measures of the solution's convergence, as it directly quantifies the error in the solution of the system equations. In CFD simulation analysis, the residual measures the local imbalance of a conserved variable in each control volume. Almost flat and a consistent residual plot (1210) observed by solving continuity, momentum, pressure poisson equations and get flow field quantities, such as velocity, turbulence intensity, pressure and integral quantities (lift, drag forces) at shortest iterations (i.e., around 300 iterations) with effective energy balancing. Similarly, different speed ratio conditions also stabilized residual and torque converter element torque plots are ensured. Once the residual error on control equations is in between 10-4 to 10-7, the results are fully converged with optimum iterative time for stall and other speed ratio conditions. Nearly around 250 to 300 iterations, the residual plot started converging is all speed ratio conditions. Almost constant impeller (3), turbine (4) and stator (5) absorption torque (1220, 1230, and 1240) attained at shortest iterations. (i.e., around 150 iterations). Further, the overall energy imbalance achieved is less than 0.1% of all the moment variables.
Figure 15 illustrates the torque converter performance characteristics details with flat torque capacity curve at lower speed ratios in improved squash type torque converter. Flat torque capacity ensures stabilized the impeller (3) speed and adequate input torque absorption from stall point to 0.40 speed ratios, which provides better traction force, and maximum power absorption at lower speed ratios with optimum heat rejection. The torque ratio achieved without compromising the vehicle performance similarly maximum efficiency arrived in between 0.80 to 0.89 speed ratio conditions.
Figure 16 illustrates the torque converter absorption characteristics at different speed ratio conditions. As per torque converter elements blade design, absorption curves at different speed ratio may vary. In reference with Figure 16, torque absorption by the impeller (3) from the engine (102) may varies from different speed conditions with considering the different turbine slipping speed. From stall to 0.40 speed ratio, power absorption is almost flat which ensures the better traction force, optimum heat rejection and improved oil circulation inside the elliptical torus portion.
Further, the invention can be used, but not limited to, in the following applications.
In an embodiment, a squash type hydraulic torque converter assembly (101) for automatic transmission comprises an impeller (3) configured with plurality of impeller blades (3C) extended from shell (3A) to core (3B) portion of impeller (3). A guide (15) is configured to be coupled with an impeller (3) along with a retainer (24). A turbine (4), an output member configured to be coupled with a transmission input shaft (25) by an output drive unit (16). A housing (9) and the output drive unit (16) are configured to be supported by radial bearing (34). A stator (5) configured to be mounted between the impeller (3) and the turbine (4) and one-way clutch (22A) is configured to be mounted on a spacer (22). A race (6) is configured to be mounted on the one-way clutch (22A). A brass type heat resistance bush (19,20) is configured to be assembled along with spacer (22). A hollow shaft sub-assembly (17) is configured to lock the spacer (22). A lockup clutch assembly is configured to avoid to avoid the slippage and switch over from torque converter mode to lockup mode.
In the assembly the squash type hydraulic torque converter assembly (101) is configured with a crankshaft, a flywheel and a damper unit coupled through an input coupling (7), a drive shaft (8), a housing (9), a ring gear (10), a drive case (11) and an impeller (3).
The said hollow shaft sub-assembly (17) is configured with a four-point contact ball bearing (18) with a lock-nut (21), wherein the spacer (22) is locked with hollow shaft (17) through spline connection.
The said lockup clutch assembly is configured with lockup friction discs (13) and lockup pressure plates (12) connected through a ring gear (10) and the output drive unit (16) to avoid the slippage and switch over from torque converter mode to lockup mode.
The torque converter assembly is configured to be enclosed with a rear case (1) and a front case (2), wherein the front case (2) and drive shaft (8) is supported by radial roller bearing (27). In the assembly, a retainer (26) is configured to be assembled with front case (2) to mount oil seal (30) and locking support to radial roller bearing (27).
The torque converter (101) is integrated with power take-off unit (103) consisting of different power tapping provision to run the hydraulic pump with different power rating.
The torque converter (101) is configured to maintain squash ratio (W/D) less than equal to 0.22, wherein overall width (W) in axial direction divided by an extreme flow path diameter (D) in radial direction.
In the assembly, a guide (15) is configured with curvature to act as rotating member and coupled with the impeller (3) for energy balancing, to improve the efficiency and to reduces the secondary flow losses.
In the assembly, the clearance between the lockup friction discs (13) and the lockup pressure plates (12) are configured to be in range of 0.55 to 0.65 mm to reduce the viscous drag torque during disengagement of the lockup clutch assembly (610).
In the assembly, a gap between each torque converter blade portion is configured to be optimized based on computational fluid dynamic analysis and cavitation free fluid flow ensured inside the elliptical torus cross section.
In the assembly, gap between the impeller blade (3C) and the turbine blade (4C) flow area (510) is configured to be in range of 0.13 to 0.15 times of overall flow area, a gap between the turbine blade (4C) to the stator blade (5C) flow area (520) is configured to be in range of .014 to 0.016 times of overall flow area and a gap between the stator blade (5C) to the impeller blade (3C) flow area (530) is configured to be in range of 0.35 to 0.37 times of overall flow area.
In the assembly the optimum blade spacing combined with a capacity factor is configured to be achieved by maintaining, an impeller pitch (P) to the chord (C) ratio (810) is configured to be in range of 0.56 to 0.58, a turbine pitch (P) to the chord (C) ratio (820) is configured to be in range of 0.66 to 0.68 and a stator pitch (P) to the chord (C) ratio (830) is configured to be in range of 0.97 to 0.99.
In the assembly, an internal pressure (P) of squash type hydraulic torque is configured to be maintained in the range of 6 to 7 bar to obtain the maximum torque converter efficiency with optimum capacity factor.
In the assembly, the blades (3C, 4C & 5C) of torque converter are configured from two-dimensional curvatures.
Exemplary assembly or system embodiments discussed above may provide certain advantages. Though not required to practice aspects of the disclosure, these advantages may include those provided by the following features.
Some object of the invention is to adopt the assembly in power-shift transmission used in construction and Off-Highway equipment.
Some object of the invention the blades with two-dimensional curvatures, which has easy manufacturability with low cost are, designed using camber line technique with variable cross section and ensure cavitation free fluid flow inside the squashed torus portion.
,CLAIMS:
A squash type hydraulic torque converter assembly (101) for automatic transmission comprising,
an impeller (3) configured with plurality of impeller blades (3C) extended from shell (3A) to core (3B) portion of impeller (3);
a guide (15) is configured to be coupled with an impeller (3) along with a retainer (24);
a turbine (4), an output member configured to be coupled with a transmission input shaft (25) by an output drive unit (16);
a housing (9) and the output drive unit (16) are configured to be supported by radial bearing (34);
a stator (5) configured to be mounted between the impeller (3) and the turbine (4);
an one-way clutch (22A) is configured to be mounted on a spacer (22);

a race (6) is configured to be mounted on the one-way clutch (22A);

a brass type heat resistance bush (19,20) is configured to be assembled along with spacer (22);

a hollow shaft sub-assembly (17) is configured to lock the spacer (22); and

a lockup clutch assembly is configured to avoid to avoid the slippage and switch over from torque converter mode to lockup mode.

The assembly as claimed in claim 1, wherein the squash type hydraulic torque converter assembly (101) is configured with a crankshaft, a flywheel and a damper unit coupled through an input coupling (7), a drive shaft (8), a housing (9), a ring gear (10), a drive case (11) and the impeller (3).
The assembly as claimed in claim 1, wherein said hollow shaft sub-assembly (17) is configured with a four-point contact ball bearing (18) with a lock-nut (21), wherein the spacer (22) is locked with hollow shaft (17) through spline connection.
The assembly as claimed in claim 3, wherein said lockup clutch assembly is configured with lockup friction discs (13) and lockup pressure plates (12) connected through a ring gear (10) and the output drive unit (16) to avoid the slippage and switch over from torque converter mode to lockup mode.
The assembly as claimed in claim 1, wherein said the torque converter assembly is configured to be enclosed with a rear case (1) and a front case (2), wherein the front case (2) and drive shaft (8) is supported by radial roller bearing (27).
The assembly as claimed in claim 1, a retainer (26) is configured to be assembled with front case (2) to mount oil seal (30) and locking support to radial roller bearing (27).
The assembly as claimed in claim 1, wherein said torque converter (101) is integrated with power take-off unit (103) consisting of different power tapping provision to run the hydraulic pump with different power rating.
The assembly as claimed in claim 1, wherein said torque converter (101) is configured to maintain squash ratio (W/D) less than equal to 0.22, wherein overall width (W) in axial direction divided by an extreme flow path diameter (D) in radial direction.
The assembly as claimed in claim 1, wherein a guide (15) is configured with curvature to act as rotating member and coupled with the impeller (3) for energy balancing, to improve the efficiency and to reduces the secondary flow losses.
The assembly as claimed in claim 1, wherein the clearance between the lockup friction discs (13) and the lockup pressure plates (12) are configured to be in range of 0.55 to 0.65 mm to reduce the viscous drag torque during disengagement of the lockup clutch assembly (610).
The assembly as claimed in claim 1, wherein a gap between each torque converter blade portion is configured to be optimized based on computational fluid dynamic analysis and cavitation free fluid flow ensured inside the elliptical torus cross section.
The assembly as claimed in claim 1, wherein a gap between the impeller blade (3C) and the turbine blade (4C) flow area (510) is configured to be in range of 0.13 to 0.15 times of overall flow area, a gap between the turbine blade (4C) to the stator blade (5C) flow area (520) is configured to be in range of 0.014 to 0.016 times of overall flow area and a gap between the stator blade (5C) to the impeller blade (3C) flow area (530) is configured to be in range of 0.35 to 0.37 times of overall flow area.
The assembly as claimed in claim 1, wherein the optimum blade spacing combined with a capacity factor is configured to be achieved by maintaining,
an impeller pitch (P) to the chord (C) ratio (810) is configured to be in range of 0.56 to 0.58, a turbine pitch (P) to the chord (C) ratio (820) is configured to be in range of 0.66 to 0.68 and a stator pitch (P) to the chord (C) ratio (830) is configured to be in range of 0.97 to 0.99.
The assembly as claimed in claim 1, wherein an internal pressure (P) of squash type hydraulic torque is configured to be maintained in the range of 6 to 7 bar to obtain the maximum torque converter efficiency with optimum capacity factor.
The assembly as claimed in claim 1, wherein the blades (3C, 4C & 5C) of torque converter are configured from two-dimensional curvatures.
The assembly as claimed in claim 1, wherein the assembly provides flat torque absorption capacity at higher load demand conditions ensures better traction force, optimum heat rejection and improved oil circulation inside the elliptical torus portion.