METHOD FOR FORMING POWER TRANSMISSION COMPONENTS USING HEAT-ASSISTED CALIBRATION PROCESS AND POWER TRANSMISSION COMPONENTS MADE USING METHOD
20170073790 ยท 2017-03-16
Inventors
Cpc classification
F16D23/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
C21D1/74
CHEMISTRY; METALLURGY
F16H57/0452
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/082
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16D2300/26
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16D13/683
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H39/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/037
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16D2300/12
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H41/24
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/032
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
International classification
F16H39/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
C21D1/74
CHEMISTRY; METALLURGY
F16H57/032
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/08
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/04
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16D23/00
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H41/24
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
F16H57/037
MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
Abstract
A method for forming a component utilizing ultra-high strength steel and components formed by the method. The method includes the step of providing a flat blank of ultra-high strength 22MnB5 steel. The next step of the method is, cold forming the flat blank into an unfinished shape of a component while the blank is in an unhardened state. The method continues by providing an inert atmosphere. Then, heating the unfinished shape of the component in the inert atmosphere. The method proceeds by forming a finished shape of the component using a quenching die resulting in a fine-grained martensitic component material structure and enabling net shape processing to establish fmal geometric dimensions of the components.
Claims
1. A method for forming a component utilizing ultra-high strength steel including the steps of: providing a flat blank of ultra-high strength steel; forming the flat blank into an unfinished shape of a component; providing an inert atmosphere; heating the unfinished shape of the component in the inert atmosphere; and forming a finished shape of the component using a quenching die.
2. The method as set forth in claim 1 wherein the step of heating the unfinished shape of the component in the inert atmosphere is further defined as heating the unfinished shape of the component in the inert atmosphere at a temperature between 850 degrees Celsius and 950 degrees Celsius.
3. The method as set forth in claim 1 wherein the step of forming a finished shape of the component using a quenching die is further defined as forming a finished shape of the component using a quenching die while cooling the component to a temperature between 150 degrees Celsius and 250 degrees Celsius.
4. The method as set forth in claim 1 wherein the step of forming the flat blank into an unfinished shape of a component further includes the step of forming a plurality of spline teeth in the unfinished shape.
5. The method as set forth in claim 1 wherein the step of forming a finished shape of the component using a quenching die is further defined as forming a finished shape of the component using a quenching die while forming a plurality of spline teeth in the component using the quenching die.
6. The method as set forth in claim 1 wherein the step of heating the unfinished shape of the component in the inert atmosphere is defined as locally heating at least one particular area of the unfinished shape in the inert atmosphere to localize strength in the particular area of the component.
7. The method as set forth in claim 1 further including the step of coating the flat blank of ultra-high strength steel with aluminum silicon to prevent corrosion and decarburization as the ultra-high strength steel is heated.
8. The method as set forth in claim 1 wherein the flat blank of ultra-high strength steel is of the 22MnB5 ultra high strength steel type.
9. A component of ultra-high strength steel being produced by: providing a flat blank of ultra-high strength steel; forming the flat blank into an unfinished shape of the component; providing an inert atmosphere; heating the unfinished shape of the component in the inert atmosphere; and forming a finished shape of the component using a quenching die so as to obtain the component.
10. The component as set forth in claim 9 wherein the component is a clutch housing and the flat blank is a strip of ultra-high strength steel and the component is further produced by forming the unfinished shape into a cylindrical shape having a radial ring portion and a cylindrical drum portion and forming a plurality of spline teeth in the cylindrical drum portion of the clutch housing using the quenching die while forming the finished shape.
11. The component as set forth in claim 9 wherein the component is a clutch hub and the flat blank is a strip of ultra-high strength steel and the component is further produced by forming the unfinished shape into a cylindrical shape having a radial ring portion and a cylindrical drum portion and including a tubular neck and forming a plurality of generally triangular openings in the radial ring portion of the unfinished shape and forming a plurality of spline teeth in the cylindrical drum portion of the clutch hub using the quenching die while forming the finished shape and attaching a drive gear to the tubular neck.
12. The component as set forth in claim 9 wherein the component is a CVT plunger and is further produced by forming the unfinished shape with a thick center and a thick outer edge and forming the finished shape of a generally bell-shaped body defining a centrally disposed opening with the quenching die.
13. The component as set forth in claim 9 wherein the component is a CVT cylinder and is further produced by removing centrally disposed material from the flat blank and forming the unfinished shape into a cylindrical shaped body having a first end and a second end and a shoulder formed at the first end and an opening longitudinally extending from the first end to the second end.
14. The component as set forth in claim 9 wherein the component is a planetary carrier having a first piece and a second piece and is further produced by forming the first piece into the unfinished shape with a plurality of apertures circumferentially disposed in a spaced relationship about the first piece and including a plurality of legs extending longitudinally and forming the second piece into the unfinished shape with a plurality of apertures circumferentially disposed in a spaced relationship about the second piece and joining the first piece with the second piece after forming the finished shape of the first piece and the finished shape of the second piece using the quenching die.
15. The component as set forth in claim 9 wherein the component is a reaction shell and is further produced by forming the unfinished shape into a body having a cylindrical first portion of a first diameter and a cylindrical second portion of a second diameter being larger than the first diameter and forming a plurality of bores in the cylindrical first portion and in the cylindrical second portion and forming a plurality of radially outwardly extending spline teeth in the cylindrical second portion of the reaction shell using the quenching die while forming the finished shape.
16. The component as set forth in claim 9 wherein the component is a differential housing and is further produced by forming the unfinished shape into a drum shape with a tubular neck portion defining a central opening and including a plurality of arms extending radially and longitudinally from the neck portion and wherein the arms alternate circumferentially between the arm including a radially inwardly extending shoulder and the arm having a generally L shaped cross section and forming at least one aperture in each of the arms.
17. The component as set forth in claim 9 wherein the component is a differential cover for enclosing a plurality of pinion gears and is further produced by forming the unfinished shape into a bell shaped body extending between a generally cylindrical first end and an opposite annular second end and attaching a ring gear to the tubular neck following forming the finished shape using the quenching die.
18. The component as set forth in claim 9 wherein the component is a torque converter cover having a front portion and a back portion and is further produced by forming the front portion into the unfinished shape having a general drum shape including a radial wall having an outer peripheral portion defining a lock-up surface and an integral cylindrical portion having an inner surface extending longitudinally from the radial wall and forming the back portion into the unfinished shape having a ring shape with a center opening and a curved cross section and forming a plurality of spline teeth in the inner surface of the front portion using the quenching die while forming the finished shape of the front portion.
19. The component as set forth in claim 9 wherein the component is an oil pan and is further produced by forming the unfinished shape into a generally rectangular base with a side wall disposed around the periphery of the base and extending generally perpendicularly from the base to an upper continuous flange adapted to be secured to a block of an engine and forming a plurality of openings defined by the flange and spaced from each other circumferentially about the flange.
20. The component as set forth in claim 9 wherein the ultra-high strength steel is of the 22MnB5 type.
Description
DRAWINGS
[0026] Other advantages of the present disclosure will be readily appreciated, as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:
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DETAILED DESCRIPTION
[0048] Detailed examples of the present disclosure are disclosed herein; however, it is to be understood that the disclosed examples are merely exemplary and may be embodied in various and alternative forms. It is not intended that these examples illustrate and describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure.
[0049] The aspects disclosed herein include components made of ultra-high strength steel and a method of forming components utilizing ultra-high strength steel. In particular, the components may be for example, lightweight automatic clutch hubs and housings, planetary gear carriers, or torque convertor covers made of boron steel and cold formed in their unhardened state to near net-shape via an indirect method and finished sized i.e. net-shaped via heat assisted calibration (HAC) to achieve 40 to 60% mass reduction of rotating inertia. According to an aspect, the lightweight pre-formed boron steel components (with or without a plurality of spline teeth) are subsequently heated in an inert atmosphere and rapidly transferred to a water-cooled quenching die to minimize oxidation and resulting in a fine-grained martensitic component material structure. The die quenching tool enables net shape processing within geometric dimensions and tolerance requirements.
[0050] As those of ordinary skill in the art will understand various features of the present disclosure as illustrated and described with reference to any of the Figures may be combined with features illustrated in one or more other Figures to produce examples of the present disclosure that are not explicitly illustrated or described. The combinations of features illustrated provide representative examples for typical applications. However, various combinations and modifications of the features consistent with the teachings of the present disclosure may be desired for particular applications or implementations.
[0051] Example embodiments of components formed from ultra-high strength steel constructed in accordance with the present disclosure will now be more fully described. These example embodiments are primarily directed to powertrain components. Moreover, each of the exemplary embodiments is provided so that this disclosure is thorough and fully conveys the scope of the inventive concepts, features and advantages to those skilled in the art. To this end, numerous specific details are set forth to provide a thorough understanding of each of the embodiments associated with the present disclosure. However, as will be apparent to those skilled in the art, not all specific details described herein need to be employed, the example embodiments may be embodied in many different forms, and that neither should be construed or interpreted to limit the scope of the disclosure.
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[0057] The method discussed above may also include, but is not limited to cold-forming the clutch housing 10 without a plurality of spline teeth 16, heat treating the unfinished shape of the clutch housing 10 using localized induction heating, and forming and sizing the plurality of spline teeth 16 using the quenching die. Alternatively, the method may include pre-forming/cold-forming the clutch housing 10 with a plurality of spline teeth 16, heating the unfinished shape of the clutch housing 10 in an inert environment, and sizing and finalizing the shape of the housing 10 in the quenching die. Similarly, planetary gear carriers and other components may be partially or completely cold formed and then heated using either localized or entire part heating.
[0058] In addition to the clutch housing 10 disclosed above, other embodiments of components from ultra-high strength steel constructed in accordance with the present disclosure are described in more detail below.
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[0067] In each embodiment of the present disclosure, the components may be formed from 22MnB5 steel, however, it should be understood that the amount of boron (B5-B50) may be selected depending on the type of component or strength desired. Additionally, the amount of other materials which comprise the ultra-high strength steel, such as carbon, may cause variation in the martensitic percentage and hardness after quenching. During the heat treatment, the heating temperature is approximately 850-950degrees C. More specifically, the target heating temperature for 22MnB5 steel is 900 degrees C., however, the heating temperature may be increased as the amount of boron is increased. As described above, the heat treating may be partially or completely localized. The heating method may be induction or by other techniques. When it is desirable to localize strength in one particular area of a component, the heat treatment may be localized to that area. In other instances, localized heat treatment may be used for sections of a component having a thicker cross section.
[0068] During the quenching step that may be used in forming each embodiment of the present disclosure, the quench press/die defines the final shape of the part. The release temperature may range between approximately 150-250 degrees C., with a preferred target temperature of 200 degrees C. The components generally remain in the quench press/die for approximately 6-20 seconds depending on the cross sectional thickness and desired strength.
[0069] In general, materials having a strength of approximately 1000 Mpa will crack or spring back during cold forming, therefore the methods described in the present disclosure are advantageous when forming such high strength materials. Additionally, due to a reduction of cross section, the geometry of components formed with heat assisted calibration (HAC) methods disclosed herein may be more complex (i.e. ribs). Consequently, the manufacturing of some components (e.g. planetary carrier described in the fifth embodiment above) that is not possible using cold forming is made possible with HAC processes.
[0070] While examples of the disclosure have been illustrated and described, it is not intended that these examples illustrate and describe all possible forms of the disclosure. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the disclosure. Additionally, the features and various implementing embodiments may be combined to form further examples of the disclosure.