Patent Application
20230039866
The present disclosure relates generally to a new method of manufacturing splined components and splined components manufactured in accordance with this new method. More particularly, the present disclosure relates to components manufactured using a draw forming process, a roller die spline forming process, and a coining operation all of which are capable of being sequentially provided in a transfer press unit.
This section provides background information related to the present disclosure which is not necessarily prior art.
Power transfer devices of the type used in automotive applications, such as for example, automatic transmissions, torque couplings, power take-off units and transfer cases, are commonly equipped with a power-operated multi-plate clutch assembly. Typically, the multi-plate clutch assembly includes a first clutch number (such as a clutch hub) driven by an input component, a second clutch member (such as a clutch drum) driving an output component, a multi-plate clutch pack disposed therebetween, and a powered clutch actuator for engaging the clutch pack and transmitting drive torque from the clutch hub to the clutch drum. The clutch drum and clutch hub are typically annular components having torque-transmitting spline teeth that are configured to engage and mesh with corresponding clutch teeth formed on the clutch plates of the clutch pack.
To reduce the mass of such clutch members while maintaining the required high-strength and torque transmission characteristics, many modern clutch hubs and drums, hereinafter referred to cumulatively as annular clutch components, are formed from sheet-metal blanks using a combination of various metal-forming and metal-cutting processes. Non-limiting examples of current high volume processes for manufacturing annular clutch components include Grob spline processing and flow form processing.
Due to the design of these formed sheet-metal clutch components, the currently available processes also present several known shortcomings. Specifically, the annular clutch components are initially formed from a steel blank that is drawn into a cup-shaped component having a radial plate segment and an axially-extending hub segment. The cup-shaped component is subsequently formed over a mandrel to produce a spline form in the hub segment via the Grob splining process. The start of the spline form from the flat flange segment to the outer diameter is in the form of a radius with a large radius on the major OD and a smaller radius on the minor OD. Typically, the annular clutch component requires an additional metal-cutting or machining process after forming the splines to form a mounting segment on the plate segment configured to allow subsequent welding or joining of another torque transmitting component. In order to guarantee the flatness of the plate segment of the annular clutch component, a metal-cutting machining process is also typically required. However, machining of the plate segment requires the cutter tool to cut along the entire length of the plate segment and encounter the edge of the spline form on both the major and minor OD surfaces. This “cut” edge profile results in an interrupted cut which, in turn, causes the machined edge material to be pushed down into the spline form as a burr. As such, a subsequent deburring operation is required to remove the burrs in the spline form area. Burrs that are not removed prior to assembly of the clutch assembly can have a detrimental impact on the function and service life of the clutch assembly.
One method of forming external splines is a broaching process. In the broaching process, material is removed from the outer surface of the component to define the external splined surface. However, this process may result in a poor surface finish on the minor diameter of the external spline, as well as on the flanks of the external spline. The resulting poor surface finish can prevent smooth sliding motion of a friction plate that is in contact with the spline surfaces. Additionally, the broaching process can have high cycle times, such as 20-30 seconds, as well as a high manufacturing cost.
Another method forming external splines is a one-shot forming process. In a one-shot process, the material of the spline is formed, and can provide an improved surface finish relative to the broaching process. However, the surface finish is still not as smooth as typically desired. The cycle time of such forming can be about 15-20 seconds, and includes a high manufacturing cost.
A further method of forming splines uses a cam die or roller die. The cycle time for such process can be as low as 4 seconds, and can have a relatively low cost relative to the broaching or one shot processes. Similar to the one shot process, this process is a material forming process, rather than a material removal process like broaching. However, in this approach, the internal diameter of the part is not continuous. Rather, the sidewall of the part has a generally constant thickness, with major and minor outer diameters as well as major and minor inner diameters defined by the process.
To this end, a need exists to develop a metal forming process capable of forming an annular clutch component which is an advancement over conventional cold forming (Grob spline forming) processes.
This section provides a general summary of the present disclosure, and is not intended to be interpreted as a comprehensive listing of all of its aspects, features, advantages and objectives.
It is an aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component.
It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component having a high-quality surface finish.
It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component having a continuous internal diameter.
It is another aspect of the present disclosure to provide a method of manufacturing a high strength torque-transmitting component using a short-cycle time a low manufacturing cost.
According to these and other aspects of the disclosure, a splined annular component is provided, comprising: a radial flange segment; an axially-extending hub segment integrally formed with the radial flange segment; a plurality of splines formed on a radially outer surface of the hub segment, wherein the splines include a major outer diameter and a minor outer diameter; and a continuous inner diameter formed on a radially inner surface of the hub segment; wherein the minor outer diameter is smooth and formed without machining; wherein the inner diameter is smooth and formed without machining.
In one aspect, the hub portion has a radial thickness that varies around a circumference thereof, wherein a first radial thickness measured between the inner diameter and the minor diameter is less than a second radial thickness measured between the inner diameter and the outer diameter.
In one aspect, the component includes a chamfer portion disposed at an intersection of the flange segment and the hub segment, wherein the chamfer portion is formed without machining.
In one aspect, the chamfer portion has an outwardly facing concave profile and an inwardly facing convex profile.
In one aspect, the minor diameter and the major diameter include a mirror-like finish.
In one aspect, the component is formed from a blank having a sodium stearate soap coating applied thereto.
In one aspect, the component is formed in a transfer press.
In one aspect, the flange segment, hub segment, and splines are pressed and formed from a common blank.
In one aspect, the inner diameter includes vertically extending witness marks circumferentially aligned with the minor diameter.
According to yet another aspect of the disclosure, a method of manufacturing a torque-transmitting component is provided, the method comprising the steps of: providing a flat blank having a flat profile to a transfer press having a first station, second station, third station, and fourth station, the first, second, third, and fourth stations including a first, second, third, and fourth die and a first, second, third, and fourth punch, respectively; at the first station of the transfer press, pressing the blank between the first die and the first punch and forming an unfinished component having a radial flange segment and an axial hub segment, the unfinished component in the form of a first cup-shaped preform; transferring the first preform to the second station and pressing the first preform between the second die and the second punch and defining a second preform of the unfinished component having a chamfer portion disposed between the flange segment and the hub segment; transferring the second preform to the third station and pressing the second preform between the third die and the third punch and defining a rough splined preform of the unfinished component having a plurality of rough splines extending radially outward from the hub segment; and transferring the rough splined preform to the fourth station and pressing the rough splined preform between the fourth die and the fourth punch and defining a smooth splined component having a final radial flange segment and a final axial hub segment; wherein the smooth splined component includes, along the final axial hub segment, a constant inner diameter, a smooth minor outer diameter, and a smooth major outer diameter.
In one aspect, the first, second, third and fourth punches have decreasing outer diameters.
In one aspect, the pressure applied at the first, second, third, and fourth stations varies.
In one aspect, the third and fourth dies include vertical extending projections sized and arranged to shape the splines.
In one aspect, at the third station, the hub segment is axially elongated in response to the pressing.
In one aspect, the first die and the first punch define a void at a location of a transition from the flange segment to the hub segment.
In one aspect, the second die includes a support portion at the location of the transition to shape the chamfer portion.
In one aspect, the third station includes a counter-pressure sleeve surrounding the third punch, the method further comprising holding the counter-pressure sleeve above the hub segment.
In one aspect, the method includes pushing material of the rough splines into space defined by the fourth die.
In one aspect, no machining operation is performed on the minor diameter of the splines.
In one aspect, the method includes trimming an upper end of the smooth splined component.
Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.
The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.
Corresponding reference numerals indicate corresponding parts and/or sub-assemblies throughout the several views of the drawings.
Example embodiments will now be described more fully with reference to the accompanying drawings.
Example embodiments are provided so that this disclosure will be thorough, and will fully convey the scope to those who are skilled in the art. Numerous specific details are set forth such as examples of specific components, devices, and methods, to provide a thorough understanding of embodiments of the present disclosure. It will be apparent to those skilled in the art that specific details need not be employed, that example embodiments may be embodied in many different forms and that neither should be construed to limit the scope of the disclosure. In some example embodiments, well-known processes, well-known device structures, and well-known technologies are not described in detail.
The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” may be intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms “comprises,” “comprising,” “including,” and “having,” are inclusive and therefore specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order discussed or illustrated, unless specifically identified as an order of performance. It is also to be understood that additional or alternative steps may be employed.
When an element or layer is referred to as being “on,” “engaged to,” “connected to,” or “coupled to” another element or layer, it may be directly on, engaged, connected or coupled to the other element or layer, or intervening elements or layers may be present. In contrast, when an element is referred to as being “directly on,” “directly engaged to,” “directly connected to,” or “directly coupled to” another element or layer, there may be no intervening elements or layers present. Other words used to describe the relationship between elements should be interpreted in a like fashion (e.g., “between” versus “directly between,” “adjacent” versus “directly adjacent,” etc.). As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Although the terms first, second, third, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms may be only used to distinguish one element, component, region, layer or section from another region, layer or section. Terms such as “first,” “second,” and other numerical terms when used herein do not imply a sequence or order unless clearly indicated by the context. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
Spatially relative terms, such as “inner,” “outer,” “beneath,” “below,” “lower,” “above,” “upper,” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. Spatially relative terms may be intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “below” or “beneath” other elements or features would then be oriented “above” the other elements or features. Thus, the example term “below” can encompass both an orientation of above and below. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
In general, the teachings of the present disclosure are directed toward a method of manufacturing an annular component from a blank of steel and which is capable of providing non-machined straight formed splines. The present disclosure further relates to an annular clutch component fabricated using this new part forming process. In one embodiment, the annular component is a clutch hub of a multi-plate friction clutch assembly for use in vehicular drivetrain applications which may include, without limitations, automatic transmissions, transfer cases, power take-off units, torque couplings and disconnect couplings
To this end,
As further described below, a cup-shaped pre-form (formed in a drawing operation) is subsequently exposed to additional pressing and forming operations to form a continuous series of circumferentially-aligned spline forms 106 on hub segment 104. As seen, a central aperture 110 is also provided, and oil transfer holes (not shown, but similar to those shown
Referring to
First station 120a may be referred to as cup-forming station. Second station 120b may be referred to as diagonal face forming station. Third station 120c may be referred to as rough spline forming station. Fourth station 120d may be referred to as finish spline forming station. Generally, the component formed following one station is placed into the next station to undergo further forming, and is then removed and transferred to the next station for additional forming.
With reference initially to
For the purposes of further discussion, the various intermediate shapes created between the initial flat blank 121 and the final shaped and splined component 100 (for example the various shaped and splined pre-forms 124, 126, 128 described above) may be referred to collectively as unfinished component 122 as they are transferred and pressed and formed at various stations 120a-120d. Flat blank 121 may also be referred to generally as unfinished component 122, and the unfinished component 122 at the final stage of the transfer press 120 may still be referred to as the unfinished component 122 (even though it has undergone the final step of the transfer press 120 and will be removed from the transfer press as finished component 100). It will be appreciated that once the pressing and forming changes the shape of the flat blank 121 to one of the intermediate shapes of the unfinished component 129, that the shape of the unfinished component 122 will be different than the initially provided flat blank 121, as it is formed within stations and transferred among stations.
Each of the stations of the transfer press 120 may be actuated at the same time, such that the first, second, third, and fourth pressing operations are performed generally simultaneously to different forms of the unfinished component 122 that are in different stages of the forming process. The cycle time per pressing operation may therefore be reduced, such as 4 seconds. The unfinished component 122, in its various stages of forming, may be automatically transferred between stations between pressing instances by an automatic or robotic transfer mechanism (not shown).
Referring now to
In one aspect, the blank 121 may include a coating 121a on both sides of the disc-shape. The coating may be applied via salt bath, and may be used to assist in reducing heat during the forming operation described herein. In one aspect, the active ingredient in the coating 121a may be sodium stearate soap.
The thickness of the blank 121 may be chosen based on a variety of factors, including desired amount of material movement, in particular the movement that occurs during the forming of the splines 106 on the outer diameter of the component 100. During the spline-forming processes, material will be pushed, formed, and will move from a thick area into a spline region with a larger volume. Put another way, material may be pushed or pulled into open-spaces defined by the tooling to form the splines 106. Thus, material of the unfinished component 122, in the spline forming process, is generally not removed from the unfinished component 122, but rather is re-allocated to define the major and minor diameters of the exterior surface to form the rough and subsequently finished spline forms.
The flat blank 121 is introduced into the transfer press 120 and transferred between stations 120a-d, as described above, after undergoing processing into the various shapes of the unfinished component 122. Each transfer station 120a-d will now be described in further detail.
Referring to
The first die 130 (and the other dies described herein) are illustrated cross-sectionally as generally one half of a rotationally symmetrical shape. It will be appreciated that a similar arrangement is disposed on the opposite side of a central axis. As illustrated in
In one aspect, a retention ring 134, having an annular shape, may be placed above the flat blank 121 when the blank 121 is supported on the die 130. More particularly, the retention ring 134 may sandwich the blank 121 against the outer portion 130a of the die 130, and the blank 121 may extend over the die cavity 130c.
With the blank 122 supported on the die 130 and the retention ring 134 disposed on the blank 121, the blank 121 may undergo the first draw, as illustrated in
The first punch 132 is sized to be received within the die cavity 130c, and may include a bottom face 132a and an outer diameter 132b. A chamfer 132c may be defined at the intersection of the bottom face 132a and the outer diameter 132b. The chamfer 132c may be radiused at its intersection with the outer diameter 132b and may also be radiused at the intersection between the chamfer 132c and the bottom face 132a.
When the punch 132 is pressed into the die 130, the blank 122 will be drawn in and bend around the general shape of the punch 132. The chamfer 132c permits the component 122 to be formed to include a radiused edge 122b. The radiused edge 122b of the component 122 does not exactly match the shape of the chamfer 132c, and open space or void may be disposed between the punch 132 and the blank 122 at the area of the chamfer 132c.
In one aspect, the chamfer 132c may have a concave cross-sectional profile, rather than a constant slope. In either case, as the material of the unfinished component 122 bends around the chamfer 132c, space may be defined between the curved shape of radiused edge 122b and the surface of the chamfer 132c.
Additionally, the die 130 may define a void or space between the blank 122 and the die 130 at the area of the chamfer 132c. The radiused edge 122b of the unfinished component 122 can be further shaped and processed in subsequent pressing processes, such as at station 120b. Because the chamfer 132c and die 130 both define voids relative to the unfinished component 122, the actual shape and curvature of the unfinished component 122 may vary during this step for each part, with more predictable curvatures and shapes being defined in subsequent steps performed on the unfinished component 122.
It will be appreciated that the punch 132 may also have different shapes (in addition to or alternative from the chamfer 132c) to define various shapes features along the bottom face 132a and outer diameter 132b.
During the first draw shown in
With the component 122 shaped into pre-form 124 as shown in
Referring now to
The second die 140 may include a support portion 140e disposed at the inner corner between an outer portion 140a and a lower portion 140b. The support portion 140e is in contrast to the void described above. The support portion 140e is shaped to define the radiused edge 122b of component 122 into a different shape corresponding to the shape of the support portion 140e. The punch 142 includes a corner shape corresponding to the shape of the support portion 140e.
As shown in
The second die 140 may include an inner diameter defined by the outer portion 140a that is slightly smaller than the inner diameter defined by the outer portion 130a of the first die 130. The second punch 142 may have a slightly smaller diameter than the first punch 132. The reduction in diameter from the punch/die relative to the first station 120a functions to allow for rougher shape to be defined in the first station 120a and then further refined and defined in the second station 120b. The smaller diameter of the punch 142 also allows for the punch to be more easily received in the first pre-form 124.
Prior to translating the punch 142 and the die 140 together to the position shown in
Following the second draw at the second station 120b, the unfinished component 122 with its second pre-formed shape 126 may be removed from the second station 120b and transferred to the third station 120c.
Referring to
An outer portion 150a of the die 150 may define a negative shape relative to the desired shape of the splines 106 for the final formed component 100. Put another way, the die 150 may include a plurality of vertical extending projections 150f that correspond to the shape of the indentations of the desired splines 106. Each of the projections 150f may extend radially inward from the outer portion 150a of the die. The projections 150f may include a lead-in feature 150g at an uppermost end of the projection 150f.
Prior to actuating the punch 152 and/or die 150, an injector (not shown) may hold the blank 122 above the position of the die 150 prior to the pressing operation.
During the pressing operation, the punch 152 may apply about 140 tons of pressure. During the pressing operation, the die 150 will push/pull material of the blank 122 upward along the outer portion 150a of the die 150, extending the axial length of the component 122 in the area of the splines 106. The pull of material of the component 122 will further cause the material to press against the outer diameter of the punch 152, which will operate to define the inner diameter of the component 122. In one example, the top of the unfinished component 122 is about 63.9 mm above the bottom-most surface of the unfinished component. In the prior pressing step, the top of the component 122 was about 46.9 mm from the bottom-most surface of the component 122. The inner diameter of the punch 152 is slightly smaller than the inner diameter of the second punch 142, thereby allowing the third punch 152 to fit within the unfinished component 122, and allowing material to be formed and pressed against the slightly smaller diameter of the third punch 152 during the pressing operation.
In one aspect, shown in
In another aspect, the counter-pressure sleeve 153 may be excluded, and the punch 152 may provide the counter-pressure.
Following the pressing operation of the third station 120c of
Similar to the prior stations, the component 122 is positioned above or at the upper opening of a fourth die 160, with a fourth punch 162 configured to be inserted into the blank 122 and to press the blank 122 into the fourth die 160. The outer shape of the fourth punch 162 mimics the final inner shape of the component 100. Similarly, the shape of the fourth die 160 mimics the final outer shape of the component 100. The cooperating shapes of the fourth die 160 and the fourth punch 162 are arranged to form the material of the unfinished component 122 into the form of the final component 100, and the corresponding shapes of the fourth die 160 and the fourth punch 162 will define a smooth continuous inner diameter 101 of the component, a chamfered edge 103, and the outer spline profile 106 of the component 100. The fourth station 120d may also be referred to as the finish spline forming station.
Prior to the pressing operation, as shown in
The fourth punch 162 may be applied with about 95 tons of pressure. This amount of pressure is lower than the third station 120c, because the rough form of the splines 106 has already occurred. The diameter of the punch 162 is slightly smaller than the diameter of the third punch 152, and defines the smooth continuous inner diameter 101 of the component 100
At the conclusion of the pressing operation of the fourth station 120d, shown in
However, additional processing on the component 100 may still be performed. For example, the component 100 may be trimmed via a trimming operation at the upper end where the material of the component 100 had been pushed/pulled during the spline forming steps. However, no further machining of the spline 106 is necessary. Additionally, the smooth and continuous inner diameter 101 of the component 100 provides for a component where no additional machining is necessary on the inside profile of the component 100. Put another way, generally no material needs to be removed or machined away in the radial direction of the component to define the spline profile or the inner or outer diameters of the component.
Thus, the resulting component 100 includes the smooth and continuous inner diameter 101. The external splines 106 further exhibit a smooth and shiny/mirror-like appearance. This appearance is different than the result of a broaching or one-shot process. In particular, the surface finish in the root of the spline 106 and on the outer surface of the spline 106 is mirror-like and very smooth, as shown in
The improved surface finish of the splines 106 can improve performance with mating components, in particular sliding contact between the surfaces of the mating component and the splines 106 of the component 100 may be improved.
The above-described process and resulting component 100 provides various advantages. For example, the cycle time of the process is reduced. The manufacturing cost is reduced as a result of the reduced cycle time and reduction of machining operations on the spline. Additionally, the surface finish, as described above, is improved compared to, for example, the broaching process.
Referring to
The purpose of illustrating these potential uses of the components 100 of the present disclosure is to permit those skilled in the art to appreciate that these components 100 may be adapted for a plethora of automotive and non-automotive torque transmission applications.
The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.
This PCT International Patent application claims the benefit of previously filed U.S. Provisional Patent Application No. 62/978,096, filed Feb. 18, 2020, the entire content of which is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/CA2021/050170 | 2/17/2021 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62978096 | Feb 2020 | US |
