US20180036791A1

US20180036791A1 - Tool and method for forming surface features onto a workpiece

Info

Publication number: US20180036791A1
Application number: US15/228,106
Authority: US
Inventors: Timothy Simon
Original assignee: Schaeffler Technologies AG and Co KG
Current assignee: Schaeffler Technologies AG and Co KG
Priority date: 2016-08-04
Filing date: 2016-08-04
Publication date: 2018-02-08
Also published as: CN109562438A; WO2018026616A1; DE112017003913T5

Abstract

A tool for forming an annular workpiece, such as a gear, is provided. The tool has a cylindrical inner form member that has a perimeter that is surrounded by the gear. Driver moves axially along a central axis of the inner form member and gear. A plurality of outer form members rest on a support and are slideable with respect to the support. Each outer form member is provided with a tapered surface that corresponds with and engages with a tapered surface of the driver. Axial movement of the driver causes the tapered surfaces to engage, sliding the outer form members radially inwardly toward the gear. The outer form members are provided with surface features that form teeth onto the gear when the driver presses the outer form members against the gear.

Description

TECHNICAL FIELD

The present disclosure relates an apparatus and a method for forming surface features (e.g., a series of teeth and/or grooves) into an annular, external surface of a gear.

BACKGROUND

Automatic transmissions, torque converters, and the like have many parts with intricate surface features. For example, a planetary gearset may include gears or carriers that have a series of repeating grooves and teeth on the outer surface of the part. It is known to form the grooves of these parts by utilizing one or more rollers.
For example, DE102010019522 discloses a device that has an external profile including a lower die accommodating a cup-shaped blank on an arbor. The profile has an upper die that is axially adjustable opposite to the lower die, wherein the upper die has multiple rollers that are arranged over the circumference of the blank. The profile rollers are accommodated in a retaining ring that is formed from two ring parts, which are designed complementary to each other.

SUMMARY

In one embodiment, a tool for forming an annular workpiece is provided. The tool includes one or more inner form members defining a perimeter. The tool also includes a plurality of outer form members collectively disposed in an annular shape about a central axis and radially outward from the perimeter. Each outer form member has an inner surface facing the inner form member and an opposing outer surface. Each inner surface defines a surface feature for forming a corresponding outer surface feature onto the workpiece. The tool also includes a driver member configured to translate along the axis to cause the outer form members to move radially inward toward the workpiece to form the outer surface features onto the workpiece.
Each outer surface of the outer form members may be tapered with respect to the central axis, and the driver member may include an inner surface of the driver member is tapered with respect to the central axis. The inner surface of the driver member may slide along the outer surfaces of the outer form members to force the outer form members to move radially inward toward the workpiece to press-form the surface features onto the workpiece.
The perimeter or outer surface of the inner form member may define a series of surface features for forming corresponding inner surface features onto the workpiece.
The one or more outer form members may be a single cylindrical inner form member. Alternatively, the one or more outer form members may be a plurality of inner form members that collectively define the perimeter.
In another embodiment, a method of forming an annular workpiece includes locating the annular workpiece between a generally cylindrical inner form member and a plurality of outer form members, each outer form member being disposed on a support and having an outer surface. The method also includes driving a driver member toward the support and against the outer surfaces to force the outer form members to slide along the support and press against the annular workpiece.
In another embodiment, a system for forming a gear includes a support, and a plurality of outer form members supported by the support and arranged annularly about a central axis. The outer form members are configured to move toward and away from the central axis along the support. Each outer form member is biased away from the central axis. A driver is selectively engaged with at least one of the outer form members. Movement of the driver toward the support presses the outer form member toward the central axis to form an outer surface of the gear.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a partial perspective view of a tool in a closed position, or use position, in which the tool is forming teeth onto a gear, according to one embodiment.

FIG. 2 is a partial perspective view of the tool in an open position, or non-use position, in which the tool is not forming teeth onto a gear.

FIG. 3 is a perspective view of the tool with various components now shown in their entirety.

DETAILED DESCRIPTION

Embodiments of the present disclosure are described herein. It is to be understood, however, that the disclosed embodiments are merely examples and other embodiments can take various and alternative forms. The figures are not necessarily to scale; some features could be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the embodiments. As those of ordinary skill in the art will understand, various features illustrated and described with reference to any one of the figures can be combined with features illustrated in one or more other figures to produce embodiments that are not explicitly illustrated or described. The combinations of features illustrated provide representative embodiments for typical applications. Various combinations and modifications of the features consistent with the teachings of this disclosure, however, could be desired for particular applications or implementations.
It should be understood that references to directions (e.g., “downward,” “upward,” “inward,” “outward,” “inner,” “outer,” etc.) are intended to describe the embodiments of a tool and gear in their orientation shown in the figures. These terms are meant to be interpreted in light of the position of the tool and gear as shown in their particular arrangement and orientation in the Figures. For example, while a driver is described below as driving “downward,” this term is intended to mean “downward when oriented as shown in the figures,” as it should be understood that the tool may take other orientations (e.g., angled, upside-down, etc.) when actually used to form the gear. Also, the terms “inner” and “outer” are meant to be taken with respect to a central axis of the tool.
According to one or more embodiments of this disclosure, a tool, system and method for forming a toothed gear is provided. The teeth on the gear are press-formed into the gear's surfaces in a linear direction, as opposed to roll-forming in which the roll-forming tool rolls across the surface.
FIG. 1 shows a tool 10 for press-forming teeth on the gear 12. In FIG. 1, the tool 10 is shown in a use position in which the teeth are being formed onto the surfaces of the gear 12. In FIG. 2, the tool 10 is shown in an open, unused position in which the gear is nor forming the teeth on the gear. The gear is not shown in FIG. 2 to provide a clearer view of the tool 10.
The tool 10 includes a support 20, a driver 30, a plurality of outer form member 40, and an inner form member 50. These components, as well as the gear 12, may share a common central axis (not shown). These components work together to press outer teeth 14 and inner teeth 16 onto the surfaces of the gear 12. The support 20, the driver 30, and the inner form member 50 extend in a circle entirely about the gear 12, but in FIGS. 1-2 these components are only shown in part for illustrative purposes; the components are shown in their entirety in FIG. 3. Furthermore, while only one outer form member 40 is shown in the Figures, it should be understood that this is only for illustrative purposes as well; a plurality of the outer form members 40 extend about the gear 12. In one embodiment, the number of outer form members 40 corresponds to the number of outer teeth 14 on the gear.
The tool 10 operates to form teeth on the gear 12 as follows. The gear 12 is placed on the support 20 or some other underlying surface (not shown). To initiate the forming process, the driver 30 is driven or pressed downward by hydraulics, for example. As the driver 30 is driven downward, the driver 30 engages the outer form members 40 to force the outer form members 40 along in the support 20 in an inward direction toward the gear 12. When driven further, the driver 30 forces the outer form members 40 further inward to press against the gear 12. The gear 12 is pressed between the outer form members 40 and the inner form member 50, with each member 40, 50 being provided with surface features to form corresponding outer teeth 14 and inner teeth 16 onto the gear 12.
The support 20 has a generally planar upper surface 22. The upper surface 22 may be provided with tracks or grooves that extend radially outward from the central axis. These tracks or grooves guide the outer form members 40 inward and outward when they are forced inward and outward by the driver 30. The lower surfaces of the outer form members 40 may each have a corresponding protrusion that fits within one of the tracks or grooves. In another embodiment, the upper surface 22 may be provided with radially-extending protrusions that each fit within a corresponding groove or track on the bottom surface of a respective one of the outer form members 40. The interaction of the grooves or tracks with the protrusions is but one example of allowing a slideable coupling between the outer form members 40 and the support 20.
The driver 30 can move downward toward the support 20 and upward away from the support 20 to selectively press and release the outer form members 40 from the gear 12. The driver 30 includes an inner surface 32 that faces toward the central axis. In one embodiment, the inner surface 32 is tapered with respect to the central axis such that the top of the inner surface 32 is closer to the central axis than the bottom of the inner surface 32. As shown in FIG. 3, the inner surface 32 may take a frustroconical shape.
The outer form members 40 have corresponding outer surfaces 42 that engage the driver 30 as the driver is driven. The outer surface 42 of each outer form member 40 is tapered with respect to the central axis such that the top of the outer surface 42 is closer to the central axis than the bottom of the inner surface 32. The shape of the outer surface 42 of each outer form member 40 corresponds with the shape of the inner surface 32 of the driver 30. In one embodiment, the surfaces 32, 42 engage in a face-to-face relationship when the driver is driven to assure a smooth linear movement of the outer form members 40 toward the central axis.
When the driver is in a non-use or open position (e.g., FIG. 2), the driver is spaced from the outer form members 40 and does not directly engage the outer form members 40. When the driver 30 is driven, the inner surface 32 of the driver engages the outer surfaces 42 of the outer form members 40. The tapered surfaces transfer downward movement of the driver 30 into radial movement (i.e., toward the gear 12) of each of the outer form members 40, as described above.
Each outer form member also includes an inner surface 44 that is provided with surface features 46. In one embodiment, the surface features 46 are in the desired shape of the outer teeth 14 on the gear. As the outer form members 40 are pressed toward and onto the gear 12, the surface features 46 presses against the outer surface of the gear 12, forming the outer teeth 14.
In an embodiment in which inner teeth 16 are formed onto the gear 12, the inner form member 50 includes an outer surface 52 with a plurality of surface features 54. These surface features 54 are in the desired shape of the inner teeth 16. The outer surface 52 and the surface features 54 provide a resisting force against the radially-inward pressing force from the outer form members 40. Therefore, when the driver 30 presses the outer form members 40 against the gear 12, both the outer teeth 14 and the inner teeth 16 can be formed simultaneously.
A method of forming an annular workpiece, such as a gear 12, can be accomplished using the tool described above. In one embodiment, the gear 12 is placed between the generally cylindrical inner form member 50 and the plurality of outer form members 40. Each outer form member 40 is slideably disposed on the support 20. The driver 30 is driven toward the support and against the outer surfaces 42 of the outer form members 40. This forces the outer form members 40 to slide along the support and press against the gear 12. The outer form members 40 can be spaced from one another, but can collectively define a perimeter or circumference that is adjustable in size by way of driving the driver 30 up and down.
It should be understood that the gear 12 described above can be one of many types of gears, such as a ring gear, a carrier, a sun gear, etc. Many different types of gears are known to exist in a transmission or torque converter of a vehicle, and the tool and forming system disclosed above can be implemented on any type of gear. If a particular gear being formed is intended to have no inner teeth, then the inner form member 50 can be designed to have no outer surface features. Likewise, if the particular gear being formed is intended to have no outer teeth, then the outer form members 40 can be designed to have no inner surface features.
Utilizing the tool of this disclosure, as opposed to conventional roll-forming of the gears, reduces the amount of moving parts. This reduces the opportunity for damage done to the parts. The amount of rotating parts during roll-forming is more costly to maintain as compared to the forming of this disclosure.
It should be understood that relative terms such as “generally,” as in a “generally cylindrical inner form member” can include surface features, bumps or grooves on the outer surfaces, but one of skill in the art would still recognize the member as being overall “generally” cylindrical.
While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms encompassed by the claims. The words used in the specification are words of description rather than limitation, and it is understood that various changes can be made without departing from the spirit and scope of the disclosure. As previously described, the features of various embodiments can be combined to form further embodiments of the invention that may not be explicitly described or illustrated. While various embodiments could have been described as providing advantages or being preferred over other embodiments or prior art implementations with respect to one or more desired characteristics, those of ordinary skill in the art recognize that one or more features or characteristics can be compromised to achieve desired overall system attributes, which depend on the specific application and implementation. These attributes can include, but are not limited to cost, strength, durability, life cycle cost, marketability, appearance, packaging, size, serviceability, weight, manufacturability, ease of assembly, etc. As such, to the extent any embodiments are described as less desirable than other embodiments or prior art implementations with respect to one or more characteristics, these embodiments are not outside the scope of the disclosure and can be desirable for particular applications.

Claims

What is claimed is:

1. A tool for forming an annular workpiece, comprising:

one or more inner form members defining a perimeter;

a plurality of outer form members collectively disposed in an annular shape about a central axis and radially outward from the perimeter, each outer form member having an inner surface facing the perimeter and an opposing outer surface, each inner surface defining a surface feature for forming a corresponding outer surface feature onto the workpiece; and

a driver member configured to translate along the axis to cause the outer form members to move radially inward toward the workpiece to form the outer surface features onto the workpiece.

2. The tool of claim 1, wherein each outer surface of the outer form members is tapered with respect to the central axis, and the driver member includes an inner surface that is tapered with respect to the central axis.

3. The tool of claim 2, wherein the inner surface of the driver member slides along the outer surfaces of the outer form members to force the outer form members to move radially inward toward the workpiece.

4. The tool of claim 1, wherein the perimeter defines a series of surface features for forming corresponding inner surface features onto the workpiece.

5. The tool of claim 4, wherein the outer form members are radially slidable with respect to the perimeter to form the outer surface features and inner surface features onto the workpiece.

6. The tool of claim 1, further comprising a support member having a generally planar surface for supporting the outer form members.

7. The tool of claim 6, wherein the support member includes a plurality of tracks extending radially from the central axis.

8. The tool of claim 7, wherein each outer form member includes a protrusion extending into one of the tracks to facilitate sliding movement of the outer form members along the support member.

9. The tool of claim 1, wherein each outer form member is biased radially outward as the driver member moves the outer form members radially inward.

10. A method of forming an annular workpiece, comprising:

locating the annular workpiece between a generally cylindrical inner form member and a plurality of outer form members, each outer form member being disposed on a support and having an outer surface; and

driving a driver member toward the support and against the outer surfaces to force the outer form members to slide along the support and press against the annular workpiece.

11. The method of claim 10, wherein the outer surfaces are tapered with respect to a central axis of the generally cylindrical inner form member.

12. The method of claim 10, further comprising annularly arranging the outer form members about the inner form member.

13. The method of claim 10, further comprising providing a plurality of surface features on an outer surface of the inner form member, wherein the driving presses the workpiece against the surface features to form corresponding surface features on an inner annular surface of the workpiece.

14. The method of claim 10, further comprising providing a surface feature on each of the outer form members, wherein the driving presses the workpiece against the surface features to form corresponding surface features on an outer annular surface of the workpiece.

15. The method of claim 10, wherein the outer form members collectively define a circumference about the workpiece, wherein the driving reduces the circumference.

16. A system for forming a gear, the system comprising:

a support;

a plurality of outer form members supported by the support and arranged annularly about a central axis, the outer form members being configured to move toward and away from the central axis along the support, each outer form member being biased away from the central axis; and

a driver selectively engaged with at least one of the outer form members;

wherein movement of the driver toward the support presses the outer form member toward the central axis to form an outer surface of the gear.

17. The system of claim 16, further comprising an inner form member disposed radially inward from the outer surface of the gear to form inner surface features on the gear.

18. The system of claim 17, wherein the inner form member is moveable along the central axis relative to the support.

19. The system of claim 16, wherein the outer form members collectively define a circumference that is variable when the driver engages the at least one of the outer form members.

20. The system of claim 16, wherein the outer form members each define a tapered outer surface facing away from the central axis that engages with a corresponding tapered surface of the driver.