WO2006104916A2

WO2006104916A2 - Snap ring retainer slot for a splined member

Info

Publication number: WO2006104916A2
Application number: PCT/US2006/010858
Authority: WO
Inventors: Ronald Prater; Brian Nosakowski; Joseph Szuba
Original assignee: Ronjo Company
Priority date: 2005-03-25
Filing date: 2006-03-24
Publication date: 2006-10-05
Also published as: WO2006104916A3

Abstract

A housing assembly for a transmission housing that also includes a tool apparatus and a method of using the apparatus for forming a lance in a cylindrical wall of the housing assembly. The cylindrical wall defines a series of alternating ridges and recesses in a corrugated configuration. The tool apparatus defines a forming surface that includes an edge and a radial relief along a portion of the edge. The forming surface cuts and forms a lance into each of either the alternating ridges or recesses thereby in aggregate defining a slot around the cylindrical wall. The lance is defined by two opposing sides, a base joint to the two opposing sides by radial transitions formed by the radial relief on the forming surface. The radial transitions reduce the internal stresses formed into the housing assembly to improve the strength and durability of the housing assembly.

Description

SNAP RING RETAINER SLOT FOR A SPLINED MEMBER

CROSS REFERENCE TO RELATED APPLICATION [0001] This application claims the benefit of provisional application serial number 60/665,209 filed on 3/25/2005.

BACKGROUND OF THE INVENTION 1. Field of the Invention

[0002] The present invention relates to a splined member for use as a transmission housing assembly. In particular, the present invention is focused to the formation and geometry of a lance in the housing assembly, and a series of the lances in aggregate defines a slot extending annular Iy around an axis.

2. Description of the Prior Art

[0003] Complex mechanical devices, such as vehicle automatic transmission, have utilized housing assemblies that have a cylindrical wall presenting alternating ridges and recesses defining a corrugated configuration around an axis. Such housing assemblies are utilized to secure and engage different shafts in a transmission through the use of a clutch pack and various activation devices, typically a hydraulic piston. The clutch pack has a complementary corrugated configuration and engages in the hosing assembly. The clutch plate is held axially in the housing by a snap ring retainer. The snap ring retainer is seated in a slot extending annularly in the cylindrical wall.

[0004] There have been several methods of forming the slot in the cylindrical wall in the prior art. Such prior methods included costly machining; require additional deburring operations, and/or complex snap ring retainer design to engage in the slot. In addition, the prior art forming methods involved a compromise in the strength and durability of the housing assembly. The reduced strength of the housing in the past was addressed by increasing the material thickness of the housing. The additional material thickness led to additional concerns with the weight of the part. [0005] Advances to the lance design have attempted to address the reduced durability of the housing assembly caused by the cutting and/or forming of the lance. One example of such advances is disclosed in United States Patent Number 6,868,950, which describes various blanking operations that avoid the severing of both sides of the lance from the cylindrical wall. The junction formed between the sides and the cylindrical wall provides additional strength thereby reducing the effect that the lance and slot has on the durability of the housing. However, there exists a need to improve on the prior art housing assembly, tooling and procedure to form a lance and slot in a housing assembly. In addition there always exists the need to simplify the forming while still improving the durability of the housing, by addressing the typical failure of the housing which is cracking that originates from the lance. The prior art have added thickness to the housing material or redesigned the lance and the snap ring retainer. Therefore there exists a need to address the problem of cracking and fracturing of the housing assembly while under an application load that allows for use of a simple snap ring retainer, without the need to increase the mass of the housing assembly, and have minimal effect and cost impact to the manufacturing of the housing or snap ring retainer.

SUMMARY OF THE INVENTION AND ADVANTAGES [0006] The subject invention provides for a housing assembly including a cylindrical wall presenting alternating ridges and recesses. The alternating ridges and recesses define a coiτugated configuration around an axis. A lance is formed in either each of the alternating ridges or the recesses. The series of lances in aggregate defines a slot around the housing assembly. Each lance includes two opposing sides and a base disposed between the two sides. The lance further includes a radial transition between the base and the opposing sides for relieving forming stresses.

[0007] The subject invention also provides for a tooling apparatus for forming each lance that in aggregate defines a slot extending annularly around the cylindrical wall. The tooling apparatus includes a tool having a first and second planar surfaces and a forming surface disposed between the planar surfaces. The first and second planar surfaces are spaced to define a tool width. The forming surface defines an edge at each intersection of the forming surface and the first and second planar surfaces are used to cut the cylindrical wall, as the forming surface defines the two opposing sides and the base of the lance. The forming surface further defines a radial relief along a portion of the edge which defines the radial transition between the base and two opposing sides of the lance.

[0008] The subject invention further provides for a method utilizing the tooling apparatus to create the lance in the housing assembly. The method involves the steps of placing the tool in a generally perpendicular orientation to the cylindrical wall, and moving the forming surface into abutment with either the alternating ridges or recesses of the cylindrical wall. The forming surface is then used for cutting the lance into the cylindrical wall which defines the two opposing sides and the base of the lance. The forming surface simultaneously forms the radial transition between the base and two opposing sides during the cutting.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Other advantages of the present invention 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:

[0010] Figure 1 is a sectioned perspective view of a cylindrical wall of a housing assembly;

[0011] Figure 2 is a longitudinal cross-sectional view of an automatic transmission for an automobile having the housing assembly;

[0012] Figure 3A is a front detailed view of the prior art detailing a lance as indicated in Figure 1;

[0013] Figure 3B is an back detailed view of the prior art lance of

Figure 3A;

[0014] Figure 4A is an front detailed view of the cylindrical wall detailing a lance as indicated in Figure 1;

[0015] Figure 4B is an back detailed view of the embodiment of the subject invention of Figure 4A;

[0016] Figure 4C is a cross-sectional view of taken at line 4C in Figure

4A; [0017] Figure 5 is a top view of the cylindrical wall during formation of the lance that in aggregate defines a slot;

[0018] Figure 5A is a detailed view of the cylindrical wall as indicated in Figure 5;

[0019] Figure 6 is a cross-sectional view taken at line 6-6 in Figure 5;

[0020] Figure 7 is a top sectional view taken at line 7-7 in Figure 6;

[0021] Figure 8 is a top sectional view taken at line 8-8 in Figure 6;

[0022] Figure 9 is a partial top view of the cylindrical wall defining the lance in an externally protruding ridge;

[0023] Figure 9A is a detailed view of the cylindrical wall as indicated in Figure 9;

[0024] Figure 10 is a partial perspective view of a prior art tool;

[0025] Figure 11 is a partial perspective view of a tool used to form an embodiment of the lance;

[0026] Figure 12 is a perspective view of a prior art back plate and support plates;

[0027] Figure 13 is a perspective view of a back plate and support plates for forming the embodiment of the lance;

[0028] Figure 14 is a detailed perspective view of the support plate as indicated on Figure 13;

[0029] Figure 15 is a top sectional view of the support plate take at line 15-15 in Figure 14;

[0030] Figure 16 is a cross-sectional view of an alternative embodiment of the prior art;

[0031] Figure 17 is a cross-sectional view of the alternative embodiment of the prior art;

[0032] Figure 18 is a cross-sectional view of an alternative embodiment of the lance of the subject invention;

[0033] Figure 19 is a cross-sectional view of an alternative embodiment of the lance of the subject invention;

[0034] Figure 20 is a perspective view of an alternative tool embodiment for forming the alternative embodiment of the lance in Figures 18 and 19; [0035] Figure 21 is a side view of an alternative cylindrical wall;

[0036] Figure 22 is a cross-sectional view taken at line 22-22 in Figure

21 showing a portion of the alternative tool.

DETAILED DESCRIPTION OF THE INVENTION

[0037] Referring to the Figures, wherein like numerals indicate corresponding parts throughout the several views, a transmission housing assembly is shown generally at 10 in Figure 2. The housing assembly 10 in the preferred embodiment is for an automatic transmission, however, it should be understood that the novelty of the subject invention could further be used in different machinery and applications.

[0038] As shown in Figures 1 and 2, the housing assembly 10 includes a cylindrical wall 12 having an inner and outer surface 14, 16. The cylindrical wall 12 presents alternating ridges 18 and recesses 20 that define a corrugated configuration around an axis. The corrugated configuration defines a splined arrangement for a clutch plate 22 or optionally a mating housing or shaft 24 to engage the cylindrical wall 12. The housing assembly 10 includes a lance 26 in either the alternating ridges 18 or the recesses 20. Typically the alternating ridges 18 would project inwardly relative to the cylindrical wall 12 and the recesses 20 define a series of external alternating ridges 28 projecting outwardly relative to the cylindrical wall 12. However, as is known to one skilled the housing can further include inwardly projecting alternating ridges 18 and recesses 20 with the outer surface 16 being a generally smooth surface as is shown in Figure 21.

[0039] The lance 26 is formed into the cylindrical wall 12 in each of the alternating ridges 18 or the recesses 20 and each lance 26 aligns with the next lance 26 in aggregate to define a slot 30 that extends annularly around the cylindrical wall 12. As shown in Figure 1, the slot 30 is discontinuous and defined by the aggregate of the lances 26 in the alternating ridges 18 that project inwardly relative to the cylindrical wall 12. ■ However, as known to one skilled in the art the slot 30 optionally can be defined on an outer surface 16 of the housing assembly 10 by lances 26 formed into the recesses 20 that define the external alternating ridges 28, as shown in Figures 9 and 9A. [0040] Referring to Figure 2, the housing assembly 10 is fixed to a shaft 24 for utilization in a transmission assembly. The housing assembly 10 and shaft 24 rotate with one another. A plurality of clutch plates 22 having an outer edge presenting a corrugated configuration engage in the cylindrical wall 12 of the housing assembly 10 for rotation with the housing assembly 10, as is known in the art. The clutch plates 22 are secured in the housing assembly 10 by a snap retainer 32. The snap retainer 32 engages in the slot 30 formed by the lances 26 in the cylindrical wall 12. The snap retainer 32 prevents the clutch plates 22 from moving in an axial direction along the axis, and in particular allows for the activation of the clutch plates 22 to frictionally engage with a second plurality of clutches for transferring the rotational movement of the housing assembly 10 and shaft 24 to a clutch housing 34. The snap retainer 32 retains the clutch plates 22 in the housing when an axial force is applied activating the clutch plate 22. The activation in the case of an automatic transmission is typically done by a hydraulic piston applying the axial force to change a gear in the transmission. However it is understood that the subject invention could be used in additional environments and that transmission housing is just one application of the subject invention.

[0041] The housing assembly 10 with alternating ridges 18 and recesses 20 defines a splined engagement for the clutch plates 22 or mating shaft 24. The lances 26 in aggregate define a slot 30, and typically the exhibited durability and life problem of the housing is due to the weakening of the cylindrical wall 12 caused by the formation of the lance 26. As shown in Figures 3 A and 3B, the prior art lance geometry included a sharp corner 36 between the opposing sides 38 and base 40. The sharp corner 36 results in high formed and internal stresses that originate a crack when the housing is subject to application loads. The crack extends around the cylindrical wall 12 eventually causing a failure of the housing assembly 10, and ultimately the severing of a portion of the cylindrical wall 12. The cylindrical wall 12 would sever at the crack generally defined by the slot 30 with an upper portion 42 of the cylindrical wall 12 severing from a lower portion 44. Figure 3B further shows the outer surface 16 of the prior art cylindrical wall 12 and the sharp comers 36 there between the base 40 and the cylindrical wall 12.

[0042] The lance geometry of the lance 26 of the subject invention has proven to be imperative to substantially increasing the durability and life of the housing assembly 10. The prior art housing assemblies 10 have addressed durability concerns by increasing the thickness of the cylindrical wall 12, however in an application such as a vehicle transmission the additional weight is a concern to the efficiency of the vehicle. Additional attempts included forming methods and tooling changes that resulted in having to utilize unique snap retainers 32. The unique snap ring retainers were typically custom designed for each housing assembly 10, and therefore more costly to manufacture. In addition, any change affecting the manufacturing process would add cost to manufacture and assemble the housing assembly 10 resulting in a need for further design improvements. The subject invention addresses the durability concern by reducing the internal stresses formed into the housing assembly 10 during the formation of each lance 26.

[0043] Referring to Figures 4A, 4B, and 4C, the lance 26 of the subject invention is formed into the cylindrical wall 12 and the lance 26 is defined by two opposing sides 38 and a base 40 joined by a radial transition 46. The base 40 of the lance 26 is disposed a radial distance from either the inner surface 14 or the outer surface 16. The orientation of the base 40 is dependent on the location of the lance 26 for the application, as shown in the Figures 1, 4A, 4B, and 4C, the lance 26 defines a slot 30 for a snap retainer 32 on the inner surface 14 of the cylindrical wall 12. However, it is understood by one skilled in the art that the lance 26 could form a slot 30 on the outer surface 16, as shown in Figures 9 and 9A, of the cylindrical wall 12 for engagement with a component, i.e. snap retainer 32 or washer. The base 40 of the lance 26 is generally parallel with the axis of the cylindrical wall 12 and the two opposing side 38 extend in a generally perpendicular orientation relative to the base 40.

[0044] The radial transition 46 is generally an arcuate radius that will vary between a range of arcuate radii depending on the testing, application loads and forming stresses of the housing assembly 10. The use of the radial transition 46 has resulted in some unexpected and substantial increases to the durability of the housing assembly 10. The housing assembly 10 of the prior art tooling, as shown in Figure 10, results in a lance geometry and shape as shown in Figure 3 A and 3B, the lance 26 includes the sharp corners 36 that resulted in failure at approximately 150,000 cycles in a set duty cycle testing. Failure of the prior art housing assembly 10 was characterized by the upper portion 42 of the cylindrical wall 12 breaking from a lower portion 44. The slot 30 generally defined the plane of separation between the upper and lower portions 42, 44 of the cylindrical wall 12. The housing assembly 10 of the subject invention utilizes the lance geometry shown in Figure 4A, 4B and 4C that include the radial transitions 46 has successfully completed 1,200,000 cycles under the same set duty cycle testing. In addition, the failure of the subject invention was characterized by the upper portion 42 bending radially outwardly, i.e., blooming, rather than the severing of the housing.

[0045] The radial transition 46 between the opposing sides 38 and the base 40 of the lance 26 includes the arcuate radius that is greater than 0.25mm. The radial transition 46 has further been limited in some applications to ranges with arcuate radii that are between a range of 0.25mm and 0.75mm. However, the arcuate radius of the radial transition 46 for most applications will typically be in a range between 0.5mm and 0.75mm.

[0046] Referring to Figures 4A, 4B, and 4C the lance 26 is formed from a homogeneous section of the cylindrical wall 12 which is displace the radial distance to define the base 40 and the two opposing sides 38. The radial transitions 46 disposed between the opposing side 38 and the base 40 is best shown in Figure 4A. In addition, as shown in Figure 4B the lance geometry further defines a radial curve 48 between the base 40 and the cylindrical wall 12 of the housing. Referring to Figure 4C, the cross section better illustrates the lance geometry with the radial transition 46 there between the base 40 and the opposing sides 38, and the radial curve 48 disposed between the base 40 and the cylindrical wall 12. The radial curve provides for additional reduction in the forming stress by removing the sharp corner 36 of the prior art lance 26 shown in Figure 3B.

[0047] A tool apparatus 50 for forming the lance 26 of the subject invention includes a tool 52 partially illustrated in Figure 11. The tool 52 has first and second planar surfaces 54, 56 and a forming surface 58 disposed between the planar surfaces 54, 56. The forming surface 58 defines a tool width 60 for forming the base 40 and two opposing sides 38 of the lance 26. The forming surface 58 defines an edge 62 at each intersection of the forming surface 58 and the first and second planar surfaces 54, 56. The edge 62 cuts into the housing assembly 10 to form the base 40 and the two opposing sides 38, and the forming surface 58 further includes a radial relief 64 along a portion of the edge 62 for defining the radial transition 46 between the base 40 and two opposing sides 38 of the lance 26.

[0048] The tool 52 includes the forming surface 58 that defines a peak

66 and two valleys 68, as shown in Figure 11. The forming surface 58 includes at least one radial relief 64 on each of the two valleys 68. The tool 52 can optionally includes additional radial reliefs 64 and usually will include a pair of radial reliefs 64 in each valley 68. The radial relief 64 on the tool 52 defines the radial transition 46 between the two opposing sides 38 and the base 40 of the lance 26 during the forming of the lance 26. The radial relief 64 therefore includes the same arcuate radii as that of the radial transition 46. The radial relief 64 is therefore an arcuate radius that is greater than 0.25mm. The radial relief 64 has further been limited in some applications to ranges with arcuate radii that are between a range of 0.25mm and 0.75mm. However, the radial relief 64 for most applications will typically be in a range between 0.5mm and 0.75mm.

[0049] Figure 10, shows the prior art tooling which includes the sharp corner 36 between the planar surfaces 54, 56 and the forming surface 58 defining no radial relief 64. Therefore, the tool 52 forms the sharp corners 36 of the prior art lance geometry as shown in Figures 3 A and 3B. The prior art lance 26 as earlier discussed forms in high internal part stresses that result in a crack origination point, and eventual failure of the housing assembly 10.

[0050] The tool 52 of the subjection invention includes a stop surface

70 that extends from at least one of the valleys 68 and engages the cylindrical wall 12 for limiting the movement and depth the tool 52 displaces the base 40 of the lance 26 during the forming of the lance 26. As shown in Figure 10 the tool 52 includes stop surfaces 70 extending from each of the valleys 68.

[0051] The tool apparatus 50 further includes a back plate 72 located on the opposing surface of the cylindrical wall 12 during the forming process. The back plate 72 has first and second surfaces 74, 76 and a backing surface 78. The backing surface 78 is disposed between the surfaces defining a backing width 80. The backing width 80 is equal to the tool width 60 for supporting and providing a reactive force against the tool 52, as shown in Figures 5-7. The backing surface 78 has a complementary configuration to the forming surface 58 of the tool 52, as shown in Figure 13. The backing surface 78 engages into the peak 66, valleys 68 and stopping surface of the forming surface 58 to support the cylindrical wall 12 and engage with the forming surface 58 to form the lance 26. The backing surface 78 defines a valley 68 for engaging the peak 66 of the forming surface 58, and a pair of peaks 66 for engaging into the two valleys 68 of the forming surface 58. During the formation of the lance 26 the backing surface 78 and the tool 52 sandwich the cylindrical wall 12 as is shown in Figures 5 - 7. Figure 7, best illustrates the interaction of the complementary surface of the backing surface 78 with the tool 52, sandwiching the cylindrical wall 12.

[0052] The tool apparatus 50 further includes first and second support plates 82, 84 disposed on opposing surfaces of the back plate 72. The support plates 82, 84 sandwich the back plate 72 between the first and second support plates 82, 84 for supporting the back plate 72 there between, as shown in Figure 13. Optionally the back plate 72 can be slidably supported by the support plates 82, 84 allowing the back plate 72 to move during the forming of the lance 26. The first and second support plate 82, 84 each include a first end 86 and a second end 88. The first end 86 of the support plate defines a corrugated configuration that abuts against and supports the cylindrical wall 12 during the forming of the lance 26, as shown in Figure 8. Additionally the first end 86 of each of the support plates 82, 84 defines a width and a first corner 90. The first corner 90 defines a first radius 92 that during the forming of the lance 26 also forms, a radial curve 48 between the base 40 and the cylindrical wall 12, in the opposing surface of the cylindrical wall 12 as the radial transition 46. The first end 86 of each of the first and second support plates 82, 84 further defines a second corner 94 having a second radius 96. The second radius 96 is equal to the first radius 92 to allow for interchangeability between the first and second support plates 82, 84.

[0053] The first and second radius 92, 96 of the support plates 82, 84 are an arcuate radius that is greater than 0.25mm, as best shown in detail in Figure 14 and 15. The first and second radius 92, 96 have further been limited in some applications to ranges with arcuate radii that are between a range of 0.25mm and 0.75mm. However, the arcuate radius of the first and second radius 92, 96 in most applications will be in a range between 0.5mm and 0.75mm. In addition, the first and second radius 92, 96 optionally may be an equal arcuate radius to the arcuate radius of the radial transitions 46, or different dependent on variables accounted for in the application, manufacturing and forming stresses in the housing assembly 10.

[0054] Figure 12, shows a back plate 72 and support plates 82, 84 for the prior art tool 52. The sharp corners 36 and no radii on the support plates 82, 84 results in the sharp corners 36 between the base 40 and the cylindrical wall 12 as seen in Figure 3B. The sharp corner 36 of the prior art lances 26 results in the high internal stresses of the lance 26 and therefore the failure as earlier discussed with the severing of a portion of the cylindrical wall 12.

[0055] The tool apparatus 50 further includes first and second guide plates 98, 100 disposed on opposing planar surfaces 54, 56 of the tool 52, as shown in Figure 6. The first and second guide plates 98, 100 sandwich the tool 52 for slidably supporting the tool 52 during the forming process. In addition, the guide plates 98, 100 aid to reduce deformations of the cylindrical wall 12 during the forming of the lance 26.

[0056] The method and operation of forming the lance 26 using the above tool apparatus 50 includes the following steps. First by placing the tool 52 in a generally perpendicular orientation to the cylindrical wall 12. The tool 52 is placed and oriented relative to the desired surface and location of the lance 26 in the cylindrical wall 12. The tool 52 is moved such that the forming surface 58 of the tool 52 is in abutment with either the alternating ridges 18 or the recesses 20 depending on the location of the lance 26 on either the inner surface 14 as best shown in Figure 5 or the outer surface 16 as best shown in Figure 9. The back plate 72 is then placed in alignment and moved into abutment with the opposing surface of the cylindrical wall 12 across from the tool 52. The cylindrical wall 12 is sandwiched there between the tool 52 and the back plate 72, as shown in Figures 7. The first and second support plates 82, 84 disposed on opposing sides 38 of the back plate 72 as previously discussed support the back plate 72. Finally the guide plates 98, 100 are placed abutting the cylindrical wall 12 and sandwiching the tool 52 between for slidably supporting the tool 52.

[0057] The tool 52 radially moves into the cylindrical wall 12 cutting the lance 26 into the cylindrical wall 12 with the edge 62 of the forming surface 58. The edges 62 on the forming surface 58 of the tool 52 defines the lance 26 width between the two opposing sides 38 of the lance 26. The base 40 is a homogeneous section of the cylindrical wall 12 that is displaced a distance from the surface of the cylindrical wall 12 by the forming surface 58 of the tool 52. The base 40 is also formed into an image of the forming surface 58 and backing surface 78. The lance geometry includes the base 40 with the image of the forming surface 58 having a peak 66 and two valleys 68, as shown in Figure 5A. Simultaneously along with the cutting and forming of the opposing sides 38 and base 40, the forming surface 58 forms the radial transition 46 with the radial reliefs 64. The forming surface 58 cuts the cylindrical wall 12 between two opposing sides 38 of the lance 26, to partially sever the base 40 from the cylindrical wall 12, shown in Figures 5 - 7. The tool 52 is radially moved forward until the stop surfaces 70 abuts the cylindrical wall 12 displacing the base 40 the distance from the surface of the cylindrical wall 12.

[0058] The base 40 as it is displaced from the cylindrical wall 12 engages the support plates 82, 84 and the first radius 92 forming a radial curve 48 on the opposing side 38 of the cylindrical wall 12 between the base 40 and the cylindrical wall 12. The resulting lance geometry is further defined by the base 40 being partially severed from the two opposing sides 38 defining a crest 102, as shown in Figure 5A. The lance 26 further includes four radial transitions 46 joining between the two opposing sides 38 and the base 40, as shown in Figures 4A and 4B. The lance 26 can optionally include a radial curve 48 joining between the base 40 and the cylindrical wall 12 on the opposing surface of the cylindrical wall 12 as the radial transitions 46, as shown in Figure 4B.

[0059] The method further includes the step of moving the tool 52 and guide plates 98, 100 in relation to the back plate 72 and the support plates 82, 84 radially away from the cylindrical wall 12. The tool 52 and back plate 72 must maintain the same an axial height relative to the cylindrical wall 12, such that the position of the next lance 26 is in alignment with the first such that the aggregate of the lances 26 form the slot 30. The housing assembly 10 is rotated, as indicated by the rotational arrow in Figure 5, such that the next adjacent alternating ridge 18 is between the tool 52 and the back plate 72 for repeating the simultaneous cutting the and forming the lance 26. Optionally as one skilled in the art would understand the tool 52 and back plate 72 could be rotated and axially move to the next adjacent alternating ridge 18. The process finally include the rotating of the cylindrical wall 12 relative to the tool 52 and back plate 72 while sequentially cutting a lance 26 into each of the alternating ridges 18. It is further understood by one skilled in the art that the lance 26 may be cut and formed into the recesses 20 and the rotating and aligning of the cylindrical wall 12 would be with the next adjacent recess 20, such that in aggregate the lances 26 define the slot 30 extending annularly around the cylindrical wall 12.

[0060] An alternative tool apparatus 250 for forming a second embodiment of the lance 226 in a transmission housing assembly 10, as shown best in Figure 22. Elements of the alternative embodiment, which are similar to the elements of the preferred embodiment, are indicated by the same numeral used in the preferred embodiment preceded by the number 2. Referring to Figures 20 the alternative tool apparatus 250 includes a tool 252 having first and second planar surfaces 254, 256 and a forming surface 258. The forming surface 258 is disposed between the planar surfaces 254, 256 defining a tool width 260 which defines a width of the lance 226 between the two opposing sides 238. The forming surface 258 defines an edge 262 at each intersection of the forming surface 258 and the first and second planar surfaces 254, 256 for cutting into the cylindrical wall 212 to form the base 240 and the opposing sides 238 of the lance 226. The forming surface 258 includes a radial relief 264 along a portion of the edge 262 for simultaneously defining a radial transition 246 between the base 240 and two opposing sides 238 of the lance 226.

[0061] An alternative method for forming a lance 226 in the housing assembly 10 and cylindrical wall 212. The alternative tool apparatus 250 and method is commonly utilized when the outer surface 216 to the cylindrical wall 212 is smooth, as shown in Figure 21. The alternative tool 252 is placed in a generally perpendicular orientation to the cylindrical wall 212 of the housing assembly 10. The alternative tool 252 is moved so that the forming surface 258 is in abutment with either the alternating ridge 218 or the recess 220 of the cylindrical wall 12. The edge 262 of the alternative tool 252 is then used to cut the lance 226 into the cylindrical wall 212, and the forming surface 258 defines the two opposing sides 238 and the base 240 of the lance 226, as shown in Figure 22. The radial reliefs 264 of the alternative tool 252 simultaneously form the radial transition 246 between the base 240 and the two opposing sides 238 of the lance 226. The cylindrical wall 212 is then rotated one complete revolution relative to the alternative tool 252 to sequentially cutting a lance 226 into each of the alternating ridges 218 or recesses 220 of the cylindrical wall 212 to form a discontinuous slot 230 by the lance 226 in aggregate with the next adjacent lance 226, as shown in Figure 21.

[0062] The alternative embodiment of the lance 226 is best shown with the cross-sectional views in Figure 18, 19 and 22. The lance geometry of the subject invention further includes the radial transitions 246 disposed between the base 240 and opposing sides 238. Contrary to the prior art lance geometry, shown in Figure 16 and 17, the lance 226 of the prior art include the sharp corners 236 joining the opposing sides 238 and base 240. Therefore, as previously discussed the lance geometry of the subject invention reduces the forming and internal stresses of the housing assembly 10 by including the radial transitions 246 to relieve the internal forming stresses.

[0063] Obviously, many modifications and variations of the present invention are possible in light of the above teachings. The invention may be practiced otherwise than as specifically described within the scope of the appended claims.

Claims

CLAIMS What is claimed is:

1. A transmission housing assembly comprising; a cylindrical wall presenting alternating ridges and recesses defining a corrugated configuration around an axis, a lance formed in each of said alternating ridges of said cylindrical wall defining a base and two opposing sides with said lances aligned with each other and in aggregate defining a slot in said cylindrical wall extending annularly around said axis, and said lance having a radial transition between said base and said opposing sides for relieving forming stresses.

2. An assembly as set forth in claim 1 wherein said radial transition is generally an arcuate radius greater than 0.25mm.

3. An assembly as set forth in claim 1 wherein said radial transition is generally an arcuate radius in a range between 0.25 mm to 0.75 mm.

4. An assembly as set forth in claim 1 wherein said radial transition is generally an arcuate radius in a range between 0.5 mm to 0.75 mm.

5. An assembly as set forth in claim 1 wherein said cylindrical wall has an inner surface and an outer surface.

6. An assembly as set forth in claim 5 wherein said base is disposed a radial distance from one of said inner surface and said outer surface.

7. An assembly as set forth in claim 6 wherein said opposing sides are generally perpendicular to said base.

8. An assembly as set forth in claim 7 wherein said alternating ridges project inwardly relative to said cylindrical wall and said recesses define a series of external alternating ridges projecting outward relative to said cylindrical wall.

9. An assembly as set forth in claim 6 wherein said base is homogeneous with said cylindrical wall.

10. An assembly as set forth in claim 9 wherein said base is partially severed from said opposing sides to form a crest and define four radial transitions between said base and said opposing sides.

11. An assemble as set forth in claim 1 includes a radial curve disposed between said base and said cylindrical wall on an opposing surface of said cylindrical wall from said radial transition.

12. An assembly as set forth in claim 1 wherein a snap retainer is disposed in said slot of said cylindrical wall.

13. An assembly as set forth in claim 12 wherein a plurality of clutch plates having an outer edge presenting a corrugated configuration for engagement with said housing.

14. An assembly as set forth in claim 13 wherein said plurality of clutch plates are secured in said housing by said snap retainer.

15. A tool apparatus for forming a lance in a transmission housing assembly, said apparatus comprising; a tool having first and second planar surfaces and a forming surface disposed between said planar surfaces defining a tool width for forming a base and two opposing sides of the lance, said forming surface defining an edge at each intersection of said forming surface and said first and second planar surfaces for cutting into the housing assembly to form the base and the opposing sides, and said forming surface including a radial relief along a portion of said edge for defining a radial transition between the base and two opposing sides.

16. An apparatus as set forth in claim 15 wherein said radial relief includes an arcuate radius greater than 0.25mm.

17. An apparatus as set forth in claim 15 wherein said radial relief includes an arcuate radius in a range between 0.25 mm to 0.75 mm.

18. An apparatus as set forth in claim 15 wherein said radial relief includes an arcuate radius in a range between 0.5 mm to 0.75 mm.

19. An apparatus as set forth in claim 15 wherein said forming surface defines a peak and two valleys.

20. An apparatus as set forth in claim 19 wherein said forming surface includes at least one radial relief on each of said two valleys.

21. An apparatus as set forth in claim 20 wherein said forming surface includes a pair of radial reliefs in each valley.

22. An apparatus as set forth in claim 19 wherein said forming surface further includes a stop surface extending from at least one of said valleys for limiting the motion of said tool.

23. An apparatus as set forth in claim 22 further including a back plate having first and second surfaces and a backing surface disposed between said first and second surfaces defining a backing width that is equal to said tool width for supporting and providing a reactive force against the tool.

24. An apparatus as set forth in claim 23 wherein said backing surface has a complementary configuration to said peak, valleys and stop surface of said forming surface for support and engagement with said forming surface.

25. An apparatus as set forth in claim 23 further including first and second support plates disposed on opposing surfaces of said back plate sandwiching said back plate between said first and second support plates for supporting said back plate.

26. An apparatus as set forth in claim 25 wherein said first and second support plates having first and second ends and each of said first ends define a corrugated configuration for engagement with and supporting said cylindrical wall during the forming of the lance.

27. An apparatus as set forth in claim 26 wherein each of said first ends of said first and second support plates each have a width defining a first corner and said first corner having a first radius for forming a radial curve between said base and said cylindrical wall.

28. An apparatus as set forth in claim 27 wherein said first radius includes an arcuate radius greater than 0.25mm.

29. An apparatus as set forth in claim 27 wherein said first radius includes an arcuate radius in a range between 0.25 mm to 0.75 mm.

30. An apparatus as set forth in claim 27 wherein said first radius includes an arcuate radius in a range between 0.5 mm to 0.75 mm.

31. An apparatus as set forth in claim 27 wherein each of said first ends of said first and second support plates define a second comer having a second radius equal to said first radius for allowing interchangeability between said first and second support plates.

32. An apparatus as set forth in claim 15 further including first and second guide plates disposed on opposing planar surfaces of said tool sandwiching said tool between said first and second guide plates for slidably supporting said tool.

33. A method for forming a lance in a transmission housing assembly having a cylindrical wall presenting alternating ridges and recesses utilizing a tool having a forming surface, said method comprising the steps; placing the tool in a generally perpendicular orientation to the cylindrical wall, moving the forming surface of the tool into abutment with at least one of the alternating ridges and recesses of the cylindrical wall, cutting the lance into the cylindrical wall with the forming surface to define two opposing sides and a base of the lance, and simultaneously forming a radial transition between the base and two opposing sides during the cutting of the lance.

34. A method as set forth in claim 33 further including the steps of placing a back plate in alignment with the tool and moving the back plate into abutment with an opposing side of the cylindrical wall across from the tool.

35. A method as set forth in claim 34 further including the step of forming a radial curve on the opposing side of the cylindrical wall between the base and the cylindrical wall.

36. A method as set forth in claim 34 further including the step of moving the tool and back plate radially away from the cylindrical wall while maintaining an axial height of the tool and back plate relative to the cylindrical wall.

37. A method as set forth in claim 36 further including the step of rotating the cylindrical wall relative to the tool and back plate and aligning the next adjacent alternating ridge between the tool and back plate for simultaneously cutting the lance and forming the radial transition.

38. A method as set forth in claim 37 further including the steps of rotating the cylindrical wall relative to the tool and back plate and sequentially cutting a lance into each of the alternating ridges for creating a slot in the cylindrical wall extending annularly around an axis.

39. A method as set forth in claim 36 further including the step of rotating the cylindrical wall relative to the tool and back plate and aligning the next adjacent recess between the tool and back plate for simultaneously cutting the lance and forming the radial transition.

40. A method as set forth in claim 37 further including the steps of rotating the cylindrical wall relative to the tool and back plate and sequentially cutting a lance into each of the recesses for creating a slot in the cylindrical wall extending annularly around an axis.

41. A method as set forth in claim 33 further including the step of rotating the housing relative to the tool for simultaneously cutting the lance and forming the radial transition in at least one of the alternating ridges and recesses.

42. A method as set forth in claim 41 further including the steps of rotating the cylindrical wall relative to the tool one complete revolution for sequentially cutting the lance and simultaneously forming the radial transition in at least one of the alternating ridges and recesses for creating a slot in the cylindrical wall extending annularly around an axis.