Patent Application
20220018426
The present invention generally relates to a launch device used in connection with the powertrain of a vehicle. More specifically, the invention relates to an assembly and retention feature for components of a launch device, such as a torque converter, used in connection with the automatic transmission of an automotive vehicle.
Generally, vehicles with automatic transmissions utilize a torque converter, or launch device, to couple the output of the engine or motor with the input of the automatic transmission. The torque converter includes a front cover that is connected to the flex plate of the engine/motor. The front cover rotates with the flex plate and is in turn connected to a back cover of the torque converter. The back cover causes rotation of the torque converter's impeller (or pump). To drive the impeller, the back cover may be unitarily or integrally formed with the impeller.
The impeller includes blades (or vanes) and its rotation drives a fluid retained within the shell defined by the front and rear covers. Driven by the impeller, the fluid is transferred to the blades of a turbine, and this transfer in turn causes rotation of the turbine. Finally, the rotational output of the turbine is coupled to the input of the automatic transmission.
To enable torque multiplication, a stator is located between the impeller and the turbine. The stator, which is mounted on a one-way clutch, redirects fluid from the turbine back to the impeller. This redirection of the fluid is conducted in such a manner that it results in a multiplication of the torque.
Presented in
Internally, the rear cover 906 is provided with a series of blades or vanes 910 so as to form the impeller 912. During rotation of the impeller 912, hydraulic fluid received through flow paths (not designated) from the automatic transmission (not shown) is centrifugally forced outward, then forward to impact against opposing blades 914 of the turbine 916. In
The shape of the turbine's blades 914 causes both rotation of the turbine 916 and redirection of the fluid. This redirection is both inward and back to the impeller 912. The turbine is also mounted to a hub 918, which is in turn mounted to an input shaft (not shown) of the automatic transmission.
Positioned between the lower portions of the blades 914 of the impeller 912 and turbine 916 is a stator 920. The stator 920 receives hydraulic fluid being returned to the impeller 912 and redirects the fluid. This redirection is conducted in such a manner that it does not impede rotation of the impeller 912.
Forward of the turbine 916, between the turbine 916 and the front cover 902, the torque converter 910 also includes a rotational damper 922 and a lockup clutch assembly 924, of which the lockup clutch assembly 924 is forward most on the engine side of the torque converter 900.
Relative rotation between hubs of the rear cover 906, turbine 916 and the rotational damper/lockup assembly 922, 924 is provided in the torque converter 900 by axial thrust bearings 926, which may include either roller balls or cylinders as the rolling elements.
During operation of the torque converter 900, as the engine speed increases, the fluid pressure inside the torque converter similarly increases. Along with the increased fluid pressure, the hydrodynamic function of the fluid coupling between the impeller 912 and the turbine 916 causes the components within the torque converter to experience a thrust load and to axially separate. This separation in turn causes the overall package of the torque converter shell to expand or balloon. The expansion must be accommodated on both the engine and transmission sides of the torque converter. Illustratively, if torque converter may expands 2 mm, a total of 4 mm of axial expansion would need to be accounted for in protecting the torque converter.
To control this expansion, the front and rear covers 902, 906 have typically been provided with a thickness that limits overall expansion to a design specification, which in the above illustrative example would be not more than 2 mm. The specific thickness of the front and rear covers accordingly will depend on the particular application in which the torque converter is used and expansion associated therewith. In all applications, however, increased thickness increases both the weight and the package size of the torque converter, which is contrary to the design optimization of the torque converter.
As discussed herein, a launch device construction is provided that allows for light weighting and package size reduction while still controlling the expansion of the launch to not more than 2 mm. Through the provided construction, expansion of the torque converter can be controlled while allowing for a decrease in the thickness of the front and rear covers, resulting in the above-mentioned weight and package size reduction.
In one aspect of the invention, a launch device is provided for coupling together the rotary output member of a prime mover and the rotary input member of a transmission
In another aspect, the launch device includes a front cover configured to connect to the rotary output member of the prime mover, a rear cover connected to the front cover and rotatable therewith, the front and rear covers cooperating to define a chamber, one of the front and rear covers integrally or unitarily defining an impeller having a plurality of impeller blades extending into the chamber, a turbine having a hub configured to be connected to the rotary input member of the transmission, the turbine integrally or unitarily including a plurality of turbine blades generally opposing the impeller blades, the impeller blades being shaped to direct a fluid contained within the chamber toward the turbine, and the turbine blades being shaped to redirect the fluid back toward the impeller blades; at least one bearing rotationally supporting one of the turbine and the rear cover for rotation about a central axis, the bearing including a rolling element and inner and outer members supporting the rolling element, and a retention feature including resilient teeth extending in a radially angled direction relative to a first axial direction and allowing in the first axial direction assembling of the bearing to a supporting structure within the launch device, the teeth preventing disassembling of the bearing and the support structure in a second axial direction that is opposite to the first axial direction.
In a further aspect, the radially angled direction of the teeth extends one of toward and away from a central axis of the launch device.
In an additional aspect, the retention feature includes a locking ring mounted on one of the bearing and the supporting structure, the locking ring further including a ring portion and the teeth extending from the ring portion.
In yet another aspect, the teeth are deflectable toward the one of the bearing and the supporting structure on which the locking ring is mounted.
In still a further aspect, the teeth engage the other of the bearing and the supporting structure.
In an additional aspect, the ring portion is received in a groove defined in a portion of the bearing.
In still another aspect, the ring portion is received in a groove defining in a portion of the supporting structure.
In yet a further aspect, the teeth engage a groove defined in a portion of the bearing.
In yet an additional aspect, the teeth engage a groove defined in a portion of the supporting structure.
In another aspect, the teeth engage a surface of the bearing.
In a further aspect, the surface of the bearing is a modified surface increasing the coefficient of friction between the surface and the teeth.
In yet an additional aspect, the teeth engage a surface of the supporting structure.
In another aspect, the surface of the supporting structure is a modified surface increasing the coefficient of friction between the surface and the teeth.
In a further aspect, the supporting structure is one of the hub supporting the turbine, the front cover, the rear cover, the alignment stub engaging the front cover, or an inner race of a one-way clutch assembly.
In still an additional aspect, the bearing is a roller bearing.
In another aspect, the inner and outer members are inner and outer races of the roller bearing.
In a further aspect, the bearing is a ball bearing.
In an additional aspect, the bearing is a needle bearing.
In another aspect, the bearing is a needle roller thrust bearing.
In a further aspect, the inner and outer members are cap carriers, the cap carriers including circumferentially extending axial and radial portions.
In another aspect of the invention, a launch device is provide having a front cover configured to connect to the rotary output member of the prime mover, a rear cover connected to the front cover and rotatable therewith, the front cover and the rear cover cooperating to define a chamber, one of the front and rear covers integrally or unitarily defining an impeller having a plurality of impeller blades extending into the chamber, a turbine having a hub configured to be connected to the rotary input member of the transmission, the turbine integrally or unitarily including a plurality of turbine blades generally opposing the impeller blades, the impeller blades being shaped to direct a fluid contained within the chamber toward the turbine, and the turbine blades being shaped to redirect the fluid back toward the impeller blades, at least one bearing rotationally supporting one of the turbine and the rear cover for rotation about a central axis, the bearing including a rolling element and inner and outer members supporting the rolling element; and a retention feature allowing for assembly of the bearing to a supporting structure within the launch device in a first axial direction, the retention feature preventing disengagement of the bearing and the support structure in a second axial direction that is opposite to the first axial direction.
In another aspect of the invention, a launch device is provided having a front cover configured to connect to the rotary output member of the prime mover, a rear cover connected to the front cover and rotatable therewith, the front cover and the rear cover cooperating to define a chamber, one of the front and rear covers integrally or unitarily defining an impeller having a plurality of impeller blades extending into the chamber, a turbine having a hub configured to be connected to the rotary input member of the transmission, the turbine integrally or unitarily including a plurality of turbine blades generally opposing the impeller blades, the impeller blades being shaped to direct a fluid contained within the chamber toward the turbine, and the turbine blades being shaped to redirect the fluid back toward the impeller blades, at least one bearing rotationally supporting one of the turbine and the rear cover for rotation about a central axis, the bearing including a rolling element and inner and outer members supporting the rolling element; and a self-adjusting retention feature allowing for axial movement of the bearing relative to a supporting structure in a first axial direction and preventing movement the bearing relative to the support structure in a second axial direction that is opposite to the first axial direction, whereby as components of the launch device wear and clearance between the components increases axial load reversals on the bearing cause movement of at least portion of the retention in the first direction reducing the clearance.
In one aspect of the invention, a quick and durable retaining feature is provided for assembly of the components of the launch device.
Referring now to the drawings, the principles of the present invention are generally illustrated
Terms concerning attachment of structures and components, such as “coupled,” “attached,” “connected,” “joined,” “mounted” or “interconnected” refer to a relationship where the structures are secured or attached to one another either directly or indirectly through an intervening structure, unless specifically indicated otherwise. These attachments and relationships may be movable or rigid, unless indicated otherwise. “Integral” means that multiple elements are connected together so as to form one unit. “Unitary” means a single, one piece element. Thus, the term “unitary” is to be distinguished from the term “integral.”
Referring now to
Internally, the rear cover 16 is integrally provided with a series of blades or vanes 20 so as to form an impeller 18. During rotation of the rear cover 16, and therefore the impeller 18, hydraulic fluid supplied from the automatic transmission along a first pathway is forced radially outward under the centrifugal force of the rotating impeller 18 and blades 20. The shape of the blades 20 and the inner surface of the rear cover 16 also causes the hydraulic fluid to be directed forward, in the direction of front cover 12. In
Immediately forward of the impeller 18, the launch device 10 includes a turbine 22. The turbine 22 is mounted to a hub 24, and the hub 24 is connected to a rotatable input shaft 26 of the automatic transmission of the automotive vehicle. As seen in
Similar to the impeller 18, the turbine 22 also includes a series of blades 28. The outward portion of the turbine's blades 28 are oriented to receive the hydraulic fluid from the impeller 18. The combination of the force of the hydraulic fluid from the impeller 18 and the shape of the turbine's blades 28 drives the turbine 22 in a rotational direction that is the same as the rotational direction of the impeller 18. Hydraulic fluid received by the turbine 22 is then redirected downward and rearward, back toward the impeller 18.
Position between the lower portions of the blades 20 of the impeller 18 and the blades 28 of the turbine 22 is a stator 30. The stator 30 receives the hydraulic fluid being returned from the turbine 22 to the impeller 18. The stator 30 redirects the fluid so that it is in the same rotational direction as the impeller 18. This redirection is conducted in such a manner that it is efficiently received by the impeller 18 and does not impede rotation of the impeller 18. With this fluid coupling, rotation from the output of the engine is transferred as rotation of the input shaft 30 of the automatic transmission.
Integrated with the stator 30 is a clutch assembly 50 that limits the directional rotation of the stator 32 a single direction. The one-way clutch assembly 50 includes an outer race 52, upon which the stator 30 is supported, and an inner race 54. The inner race 54 of the one-way clutch assembly 50 is mounted upon a fixed, nonrotating support shaft 56 associated with the input of the automatic transmission. In the interest of brevity and since one-way clutch assemblies are well known in the technological field of the present invention, the one-way clutch assembly 50 of the present launch device 10 is not illustrated and need not be explained in any greater detail herein. Those skilled in the art will really appreciate the construction and operation thereof.
Forward of the turbine 22, between the turbine 22 and the front cover 12, the launch device 10 includes an isolation damper 32. The isolation damper 32 is commonly mounted to the hub 24 with the turbine 22. The isolation damper 32 absorbs variations in the rotation speed of the front and rear covers 12, 18 to provide for smoother operation of the automatic transmission and the transmission of less vibration to the occupant of the vehicle. Since isolation dampers are also well known in the field of the present invention, the isolation damper 32 of the launch device 10 is not discussed in detail herein, except as necessary.
Between the isolation damper 32 and the front cover 12, the launch device 10 additionally includes a lockup clutch assembly 34. Like isolation dampers, lockup clutch assemblies are well known in the field of the present invention. Accordingly, the lockup clutch assembly 34 is discussed below as necessary, but is not otherwise discussed in significant detail herein.
During operation of the launch device 10, in a clutch open mode, hydraulic fluid is received along one or more passageways (not shown) formed in the input shaft 26 and turbine hub 24, flows through a first bearing 44a and into a chamber 37 located between the piston 35 of the lockup clutch assembly 34 and the front cover 12. During this clutch open mode, pressure in this chamber 37 is greater than chambers elsewhere in the launch device 10, keeping the lockup clutch assembly 34 open.
From chamber 37, fluid flows radially around the piston 35 of the lockup clutch assembly 34 into chamber 38, which is generally defined between the radial sides of the front and rear covers 12, 16 and the turbine 22. Some of this fluid then also passes from chamber 38 into the hydrodynamic torus space between the impeller 18 and the turbine 22. This fluid operates with the impeller 18 and turbine 22 to define a fluid coupling within the launch device 10. Hydraulic fluid also passes from the fluid coupling into pathway 40, through a third bearing 44c and exits the launch device 10 through a passage 42. Flow in the reverse direction initially operates to close the lockup clutch assembly 34. With pressure in chamber 38 between the turbine 22 and piston 35 being greater than pressure in chamber 37, the piston 35 axially moves along an outer race 48a of the first bearing 44a. Once in clutch closed mode, the only flow is leakage or seepage through the lining material of the lockup clutch assembly 34 or various oil seals, such as the seal 51 between piston 35 and the outer race 48a of the first bearing 44a.
It should be noted that the described fluid flow is for the illustrated launch device 10. The exact fluid flow can and will vary based manufacturers and the specific design criteria of their launch device.
As mentioned above, during operation of the launch device 10 the engine speed increases. With this increase in engine speed, the axial forces and thrust loads generated by the hydrodynamic function of fluid coupling, as well as the increased fluid pressure within the launch device 10, will operate to cause axial expansion of the launch device 10.
To control and limit expansion induced by the hydraulic function and increased pressure, the launch device 10 of the present disclosure incorporates what are herein referred to as pull bearings and generally designated at 44. The integrated pull bearings 44 limit and/or prevent axial expansion of the launch devices shell by accepting the axial forces of the hydraulic function and increased pressure.
As seen in
The first bearing 44a is a pull bearing arranged between the front cover 12 and the hub 24 of the turbine 22. More specifically, the outer race 48a of the first pull bearing 44a is non-rotatably fixed to the hub 24 and serves as the inner race of the piston of the lockup clutch assembly 34. The inner race 46a of the first pull bearing 44a is non-rotatably fixed to the front cover 12, either directly or indirectly through other components of the launch device 10, such as an alignment stub 13 fixed to the front cover 12.
A second pull bearing 44b is arranged between the hub 24 of the turbine 22 and the inner race 54 of the one-way clutch assembly 50. Specifically, the outer race 48b of the second pull bearing 44b is non-rotatably fixed to the inner race 54 of the one-way clutch assembly 50, while the inner race 46b of the second pull bearing 44b is non-rotatably fixed to the hub 24.
A third bearing 44c is also a pull bearing and is arranged between the inner race 54 of the one-way clutch assembly 50 and the impeller 18. The inner race 46c of the third pull bearing 44c is non-rotatably fixed to the inner race 54 of the one-way clutch assembly 50, and the outer race 48c of the third pull bearing 44c is non-rotatably fixed to the impeller 18 and/or rear cover 16.
The inner and outer races 46, 48 of the pull bearings 44 maybe mounted on either radial surfaces or axial surfaces of the respectively associated components. Also, the non-rotatably fixation of the inner and outer races (generally 46, 48) may occur on either of these surfaces as well. Non-rotatable fixation may be achieved through a variety of fixation mechanisms, including the use of various mechanical fits or the use of welds. As shown in
As a result of the pull bearings 44 and the construction provided herein, the launch device 10 is provided with a mechanism that limits the overall expansion of the launch device 10, while also allowing for the thickness of the front and rear covers 12, 16 to be reduced along with the overall axial packaging requirements of the launch device 10.
An alternative embodiment of the launch device 10 is seen in
Referring now to
As seen in
Referring now to
The launch device 10 of
The pull bearings 80 are similarly secured and retained in their assembled positions of the launch assembly 10 by the retention features 60 forming a mechanical interaction with the axial portions 90 of the inner and outer cup carriers 86, 88 of the pull bearings 80.
As seen in
Referring now to
The retention feature 60 itself incorporates portions of the bearing component 62 and the support component 64, as well as a locking ring 66. Generally, the locking ring 66 is supported in a groove 68, 69 formed in one of the components 62, 64 and includes an annular ring portion 70 having resilient teeth 72 extending therefrom. The resilient teeth 72 are preferably unitary formed with the ring portion 70, but may be integral therewith. The teeth 72 may also extend radially inward or radially outward from the ring portion 70 at an acute angle with respect to a central axis of the launch device 10.
The teeth 72 are angled such that, during assembly of the bearing and support components 62, 64, relative movement between the bearing and support components 62, 64 in an axial direction of assembly causes a radial deflection between the ring 70 and the teeth 72 allowing the inserted component 62, 64 to move over the teeth 72 until the two components are fully assembled. Once the assembled, the teeth 72 prevent movement of the assembled bearing and support components 62, 64 in the opposite direction, thereby retaining the components 62, 64 together.
Prior to assembly of the bearing and support components 62, 64, the locking ring 66 is preferably mounted in a groove 69 formed in the bearing component 64. In this configuration, the ring portion 70 of the locking ring 66 may located in the groove 69, with the teeth 72 extending out of the groove 69 or may be located outside of the groove 69 with the teeth 72 extending into the groove 69. The latter situation is illustrated in
Preferably, the leading faces of the grooves 68, 69 in the assembly direction X, are oriented perpendicular to the direction of assembly X to define a stop face and provide resistance to movement in the opposing direction −X. When the direction of the axial load is reversed and in a disassembly direction −X, the teeth 72 of the locking ring 66 engage the leading face of groove 69 and the ring portion 70 engages a corresponding leading face of groove 68, thereby exerting resistive forces on both the bearing component 62 and the support component 64. This results in a column loading effect within the support ring 66 generating a force vector that has both an X and Y component. As the force increases in the disassembly direction −X, a “clamp” force of increasing magnitude is generated in the Y direction, operating to prevent the bearing and support components 62, 64 from separating. Thus, this action works to prevent relative axial movement the bearing and support components 62, 64 out of their fully and properly mounted positions.
Alternatively, the locking ring 66 can be initially mounted in the groove 68 on the support component 64. In this instance, the groove 68 may exhibit a greater depth at its tailing edge (shown in phantom in
It will be readily appreciated that the relative positions of the ring portion 70 and teeth 72 as seen
Referring now to
The retention feature 60 of
While not illustrated herein, the retention feature 60 may additionally include features that inhibit relative rotation between the bearing and support components 62, 64. These features may include teeth or depressions formed in the grooves 68, 69 to interact with the teeth 72 of the locking ring and/or additional teeth projecting from the ring portion 70 and generally opposed to the teeth 72.
By integrating the various portions of the retention feature 60 into the bearing races and hub connections of the launch device 10, the complexity and quantity of components can be reduced. Additionally, the proposed construction offers minimal take-up/end play, if any, in the assembled components. This design also offers benefits related to the launch device's one-way clutch. The slip engagement of the retention feature 60 is one-way and can be used to set clutch end play during initial assembly of the launch device 10. As the assembly experiences load reversals (repeated switching in the X and the −X directions), the retention feature can be considered self-adjusting. Also, as the components wear and clearance between the components increases, subsequent load reversals will reduce the clearance as the one-way slip fit of the retention feature 60 will continue to be functional. This has benefits in a launch device application in that the self-adjustability can be used to augment clutch wear, minimizing or preventing an increase in launch device end play. As clutch wear increases, drivability characteristics can suffer because of increased clutch lockup time. The retention feature 60 offers benefits to help mitigate these changes in drivability characteristics and supplement clutch wear by continuously controlling clutch end play through the life of the launch device
As a person skilled in the art will readily appreciate, the above description is meant as an illustration of at least one implementation of a launch device incorporating the principles of the present invention. This description is not intended to limit the scope or application of this invention since the invention is susceptible to modification, variation and change without departing from the spirit of this invention, as defined in the following claims.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/061269 | 11/11/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62760605 | Nov 2018 | US | |
| 62780787 | Dec 2018 | US |
