WO1996018049A1

WO1996018049A1 - Clutch plate

Info

Publication number: WO1996018049A1
Application number: PCT/US1995/016185
Authority: WO
Inventors: Charles E. Dover; Robert H. Field; Lorne L. Ebel
Original assignee: Means Industries, Inc.
Priority date: 1994-12-09
Filing date: 1995-12-08
Publication date: 1996-06-13
Also published as: AU4516496A

Abstract

A clutch plate (60) comprising a first plate (62) and at least a second plate (62), the first plate having a first plate side and defining a spline (53), the second plate having a second plate side, the first plate and the second plate being connected together such that the first plate side is adjacent to and at least partially unconnected to the second plate side.

Description

CLUTCHPLATE

Technical Field

This invention relates to a clutch plate for use in the automatic transmission of a motor vehicle.

Background Art

Automatic transmissions used in motor vehicles generally employ clutch assemblies. These clutch assemblies typically include any number of unitary clutch plates. The clutch plates typically include friction clutch plates having internal splines which are alternated with unitary separator clutch plates having external splines. The unitary separator plates and unitary friction plates are typically placed within a clutch housing which has a spline configuration designed to mate with the external splines of the separator plates thereby allowing the separator plates to slide back and forth within the clutch housing. The internal splines of the friction plates likewise slidably engage the mating splines of a clutch shaft or hub assembly located within the clutch housing.

Alternatively, the clutch plates may typically include friction clutch plates having external splines alternated with unitary separator clutch plates having internal splines. Such unitary separator plates and unitary friction plates are typically placed within a clutch housing which has a spline configuration designed to mate with the external splines of the friction plates thereby allowing the friction plates to slide back and forth within the clutch housing. The internal splines of the separator plates likewise would slidably engage the mating splines of a clutch shaft or hub assembly located within the clutch housing.

Separator clutch plates and friction clutch plates are typically made from steel. Such clutch plates are typically manufactured by using the punch and die method of manufacture. In accordance with this method, a steel punch tool having the configuration of the desired clutch plate is used to punch a clutch plate out of a sheet of metal. During the punching process, the sheet of metal is supported on a die having a hole which likewise has a configuration of the desired clutch plate, only slightly larger than the dimensions of the punch.

During the punching process, as the sheet of metal is being forced through the die, the leading or shear side of the clutch plate being formed is typically depressed slightly and the leading edge is normally radiused to some extent. As the sheet of metal is forced further through the die, a portion of the desired clutch plate is sheared from the remaining sheet metal, thereby forming a substantially smooth shear surface which is substantially perpendicular to the sheet of metal. Finally, as the sheet of metal is forced completely through the die, the last interconnecting portion between the sheet of metal and the trailing edge of the clutch plate being formed breaks, thus resulting in a die break section of the outer edge of the clutch plate. This die break section is somewhat rough and depressed relative to the shear section. As a result of the die break, the trailing edge of the clutch plate normally projects to some extent beyond the trailing or die break side of the clutch plate. Clutch plates may also be manufactured by using the fine blanking method of manufacture. This method is similar to the punch and die method except that the tolerances of the punch and die are substantially identical. As a result, substantially the total width of the edge of a clutch plate formed by the fine blanking method is sheared from the sheet of metal material being used, thereby eliminating, for the most part, any die break section. However, because the fine blanking manufacturing process requires extremely close tolerances to be effective, clutch plates manufactured through the use of the fine blanking method are more expensive than those made using the punch and die method. The blanking tools are initially more expensive, due to the close tolerances required, and the tools must be replaced more frequently to maintain the required tolerances. As a result of the extra expense involved, the punch and die approach is typically employed to manufacture clutch plates.

Furthermore, a clutch plate formed by using the punch and die method will also normally have some other small distortions caused by the stresses inherent in this method of manufacture. For example, the leading or shear side of the clutch plate may have a slight side surface rise or upset protrusion along a circle defined by the edge of where the leading or shear side depression is located. As another example, such clutch plates will often have a very small overall set, such as small overall bow or curve.

The friction plates generally incorporate a friction material, which may be a cellulose based or paper material, which is bonded to the one side or both sides of the friction plate and which will engage the separator plates during operation of the clutch assembly. Such friction plates may, as already noted, have internal splines or external splines. Such friction material is typically bonded to the clutch plate material by way of a bonding agent such as a phenolic based adhesive. Because the use of such friction materials and bonding agents are well known in the art, they will not be discussed further here.

Alternatively, friction material may be bonded to one side of each of the alternating plates having internal splines and external splines. In such an arrangement, the side of each clutch plate having friction material would be located in the clutch assembly adjacent the friction material free side of the next clutch plate.

A problem with unitary separator plates and unitary friction plates is that they often stick and slip during clutch engagement — during engagement between the separator plates and friction plates — causing vibration of the clutch assembly, sometimes called shudder. The vibration resulting from what can be referred to as the stick and slip syndrome may cause two problems. First, the vibrating clutch plates will make noises which may be audible both inside and outside the vehicle. If audible inside the vehicle, the noise may be distracting to the operator or passengers in the vehicle. If audible outside the vehicle, the noise may be objectionable to other people outside the vehicle. Second, the vibrating clutch plates may result in shudder which can be felt by the operator or passengers in the vehicle. Such shudder can be uncomfortable or distracting to the occupants. The resulting noise and shudder can be particularly objectionable to the operator of the vehicle who may believe the clutch is failing when in reality it is not. Third, vibrating separator clutch plates may rub against the clutch housing and adjacent friction plates while vibrating friction plates may rub against the clutch shaft or hub assembly and adjacent separator plates thereby resulting in galling and premature failure of the clutch system due to excessive wear, especially if an aluminum clutch housing is used.

Although wear can be reduced by using stronger structural materials, the noise and shudder caused by engagement vibration is still undesirable. This is especially true due to recent developments in engine design which allow engines to run much quieter. Noise emanating from other parts of the vehicle, such as the automatic transmission, are now especially objectionable.

Various arrangements are known in the prior art to minimize the resulting shudder, wear, and noise. However, none provide for an extremely simple assembly. Accordingly, it is desirable to provide a multi-plate clutch plate of a simple design to reduce the noise generated by the operation of the transmission, to suppress vibrations, and to reduce resulting wear.

Summary OfThe Invention

An object of the present invention is to provide an improved clutch plate for reducing shudder in a clutch assembly of an automatic transmission. More specifically, the invention is a clutch plate comprising a first plate and at least a second plate, the first plate defining a first spline and having a first plate side and the second plate having a second plate side, the first plate and second plate being connected together such that the first plate side is adjacent to and at least partially unconnected to the second plate side.

Because the clutch plate made in accordance with this invention comprises two or more thinner plates connected together, vibration of the clutch plate during use is dampened. More specifically, because the first plate side of the first plate is at least partially unconnected to the second plate side of the second plate, vibration of the first plate will tend to be dampened by its unconnected contact with the second plate and vice versa. Furthermore, by connecting the two or more thinner plates together, the thinner plates cannot move or rotate relative to each other which might otherwise cause wear. Accordingly, the clutch plate of this invention reduces both shudder and wear.

In an alternative embodiment, the clutch plate comprises a first metallic plate and at least a second metallic plate, the first plate defining a first spline and having a first plate side, the second plate having a second plate side in a second spline, the first plate and the second plate being connected together such that the first side is adjacent to the second side.

In a more specific embodiment, the first plate has an outside perimeter defining a first spline. In an alternative specific embodiment, the first plate has a first inner perimeter defining a first spline.

In each of these embodiments, the second plate may have a second spline. Accordingly, the first spline of the first plate may be aligned with the second spline of the second plate so as to engage the mating splines of the clutch housing or the clutch shaft or hub assembly located within the clutch housing. In a more specific embodiment, the connection is between the first plate and the second plate in the area of the first spline and the second spline. An advantage of having the connection in the area of the first spline and the second spline is that the connection will not interfere with the working area of the clutch plate, that being an area of the clutch plate which engages adjacent plates.

Additionally, in each of these embodiments, the first plate side of the first plate may define a first protrusion such that the first plate and the second plate will be spaced apart by the first protrusion when connected together.

As a result, because each clutch plate will comprise two or more thinner plates having adjacent surface areas which are at least partially unconnected, the surface area is approximately doubled and the lubricating/cooling fluid normally used within the clutch housing will be present between the two or more plates thereby increasing the cooling of the plates and reducing hot spotting which can negatively affect durability.

Furthermore, in each of these embodiments, the clutch plate may comprise a first plate and at least a second plate which are manufactured by the punch and die method and which are connected together. As a result of this method of manufacture, the first plate will have a first die break side and a first shear side, and the second plate will have a second die break side on a second shear side.

Because each clutch plate now comprises at least two or more thinner plates formed by the punch and die method, each clutch plate will have at least two circumferential shear bearing surfaces to facilitate the sliding of the clutch plate within the clutch housing or along a clutch shaft or hub assembly within the clutch housing.

While the first shear side may be located adjacent to the second shear side, or the first shear side may be located adjacent to the second die break side, or the first die break side may be located adjacent the second shear side, in a preferred embodiment of this alternative, the first plate is connected to the second plate such that the first die break side of the first plate is adjacent the second die break side of the second plate. The resulting clutch plate will have two circumferential shear bearing surfaces located symmetrically on each side of the clutch plate which facilitates sliding of the clutch plate within the clutch housing and along the clutch shaft or hub assembly. Also, the circumferential radiused leading edges resulting from the punch and die method of manufacture will be located symmetrically on the outermost edges of each clutch plate to further facilitate sliding. The resulting geometry minimizes interferences with, and any resulting wear to, the clutch housing and the clutch shaft or hub assembly within or on which the clutch plate slides.

Furthermore, in this preferred embodiment, the adjacent die breaks form a slight depression along the center circumferential surface of the clutch plate, thereby providing a pocket for fluids which aid in allowing the clutch plate to slide properly within the clutch housing.

In yet another alternative embodiment, the clutch plate comprises a first plate having a first set and at least a second plate having a second set and the first plate is oriented to the second plate and connected to the second plate such that the first set opposes the second set.

In this embodiment, the sets sometimes inherent in such first and second plates from the manufacturing process can be, at least to some extent, canceled out by placing the sets in opposition before connecting the thinner plates together. This will result in a clutch plate which is flatter, thereby allowing the frictional forces to be applied evenly along the surfaces of the between the friction and separator plates when engaged. This will reduce wear and noise even further.

In all of these embodiments, a mechanical stake, a rivet pin, a weld, a laser weld, adhesives, or any other connector or connector method may be used to connect the first plate and at least the second plate together. Furthermore, any one or more of the first plate or at least the second plate may be manufactured by the punch and die method, the fine blanking method, or any other method and in any combination. Furthermore, in any of the embodiments described, friction material may be bonded to one or both sides of the clutch plate. Furthermore, any of these alternative or preferred embodiments may be used in any combination with each other without deviating from the scope of this invention.

Further objects and advantages of this invention will be apparent from the following description, reference being had to the accompanying drawings wherein preferred embodiments of the present invention are clearly shown. •

Brief Description Of The Drawings

While embodiments of the invention are illustrated, the particular embodiments shown should not be construed to limit the claims. It is anticipated that various changes and modifications may be made without departing from the scope of this invention.

Figure 1 is a side view of a clutch plate having external splines, showing a typical perimeter configuration;

Figure 2 is a cross-sectional view taken along line 2-2 of Figure 1, showing a clutch separator plate comprising two or more plates, in this case four, which have been mechanically staked together;

Figure 3 is a cross-sectional view taken along line 3-3 of Figure 1, showing a separator plate comprising two or more plates, in this case four, which have been connected together through the use of rivet pins;

Figure 4 is a cross-sectional view taken along line 4-4 of Figure 1, showing a separator plate co prising two or more plates, in this case four, which have been welded together;

Figure 5 is a cross-sectional view taken along line 5-5 of Figure 1, showing a separator plate comprising two or more plates, in this case four, which have been laser welded together;

Figure 6 is a side view of a clutch plate having internal splines, showing a typical perimeter configuration;

Figure 7 is a cross-sectional view taken along line 7-7 of Figure 6, showing a clutch friction plate comprising two or more plates, in this case two, which have been mechanically staked together;

Figure 8 is a cross-sectional view taken along line 8-8 of Figure 6, showing a friction plate comprising two or more plates, in this case two, which have been connected together through the use of rivet pins;

Figure 9 is a cross-sectional view taken along line 9-9 of Figure 6, showing a friction plate comprising two or more plates, in this case two, which have been welded together;

Figure 10 is a cross-sectional view taken along line 10-10 of Figure 6, showing a friction plate comprising two or more plates, in this case two, which have been laser welded together;

Figure 11 is a cross-sectional view taken along line 11-11 of Figure 6, showing a friction plate comprising two or more plates, in this case two, which have been laser welded together and which have friction material on only one side;

Figure 12 is a cross-sectional view taken along line 12-12 of Figure 6, showing a friction plate comprising two or more plates, in this case three, which have been laser welded together;

Figure 13 is a cross-sectional view taken along line 13-13 of Figure 1, showing a friction plate comprising two or more plates, in this case two, which have been welded together, where at least one of the plates has a protrusion to provide a space between the plates;

Figure 14 is a cross-sectional view taken along line 14-14 of Figure 6, showing a friction plate comprising two or more plates, in this case two, which have been welded together, where at least one of the plates has a protrusion to provide a small space between the plates;

Figure 15 is a cross-sectional view taken along line 15-15 of Figure 1, showing a separator plate comprising two or more plates made by the punch and die method of manufacture, in this case two, which have been laser welded together such that the first die break side of the first plate is adjacent the second die break side of the second plate;

Figure 16 is a cross-sectional view taken along line 16-16 of Figure 6, showing a friction plate comprising two or more plates made by the punch and die method of manufacture, in this case two, which have been laser welded together such that the first die break side of the first plate is adjacent the second die break side of the second plate;

Figure 17 is a side view of a clutch plate having external splines, showing a typical perimeter configuration;

Figure 18 is a cross-sectional view taken along line 18-18 of Figure 17, showing a friction clutch plate comprising two or more plates, in this case four, which have been laser welded together and which have friction material on both sides;

Figure 19 is a cross-sectional view taken along line 19-19 of Figure 17, showing a friction clutch plate comprising two or more plates, in this case four, which have been laser welded together and which have friction material on only one side;

Figure 20 is a side view of a clutch plate having internal splines, showing a typical perimeter configuration;

Figure 21 is a cross-sectional view taken along line 21-21 of Figure 20, showing a separator clutch plate comprising two or more plates, in this case two, which have been laser welded together;

Figure 22 is a cross-sectional view taken along line 22-22 of Figure 1, showing a clutch separator plate comprising two or more plates, in this case four, which have been laser welded together; Figure 23 is a cross-sectional view taken along line 23-23 of Figure 6, showing a friction clutch plate comprising two or more plates, in this case two, which have been laser welded together;

Figure 24 is a representational cross- sectional view taken along line 24-24 of Figure 1 or Figure 6, showing a clutch plate comprising two or more thinner plates, in this case two, each thinner plate of which has a set and each set shown to have been placed in opposition prior to connection;

Figure 25 is a representational cross- sectional view taken along line 25-25 of Figure l or Figure 6, showing a clutch plate comprising two or more thinner plates, in this case two, each thinner plate of which has a set and each set shown to have been placed in opposition prior to connection; and

Figure 26 is a representational cross- sectional view taken along line 26-26 of Figure 1 or Figure 6, showing a clutch plate comprising two or more thinner plates, such as those shown in Figures 17 and 18, after they have been connected together.

Best Mode For Carrying Out The Invention

Figure 1 shows a typical perimeter configuration of a clutch plate 10 having an outside perimeter 11 which defines external splines 12 and an inner perimeter 13. Such clutch plates are normally metallic, typically made from steel. Because the grades of steel used are well known in the art, they will not be discussed further here. Figure 2, which is a section taken along line 2-2 in Figure 1, shows the structure of a clutch separator plate 14 made in accordance with this invention. As can be seen, the clutch separator plate 14 comprises two or more thinner plates, in this case four such thinner plates 16, which are connected together through the use of mechanical stakes 18. Such mechanical stakes 18 normally have a non-circular cross- section configuration, such as a square. The mechanical stakes 18 are press fitted into holes having the same configuration, only slightly smaller, to hold various pieces, such as the thinner plates 16, together. Because mechanical stakes 18 are generally known in the art, they will not be discussed further here. While not required, the mechanical stakes 18 are preferably located in the area of the splines 12. Referring to Figure l, the mechanical stakes 18 may be located at points on the splines indicated by the letter "X." By locating the mechanical stakes 18, or any other type of connectors, in the area of the splines 12, the connectors used will not interfere with the working area of the clutch plate, that being the area of the clutch plate which engages adjacent plates.

Figure 3, which is a section taken along line 3-3 in Figure 1, shows the structure of a clutch separator plate 14a which is substantially identical to the embodiment shown in Figure 2 except that the thinner plates 16a are connected together through the use of rivet pins 20. The rivet pins 20, which may or may not have heads 22 on one end, are inserted through holes in the thinner plates 16. The plain end or ends of the rivet pins 20 are then upset or cold headed, such as by hammering, peening or cold forging, so as to form new heads 22. The rivet pins 20 are preferably located in the area of the splines 12. Referring to Figure 1, the rivet pins 20 may be located at points on the splines indicated by the letter "X."

Figure 4, which is a section taken along line 4-4 in Figure 1, shows the structure of a clutch separator plate 14b which is substantially identical to the embodiment shown in Figure 2 except that the thinner plates 16b are connected together through the use of welds 24. As shown in Figure 4, the welds 24 may be located between adjacent plates 16b along the inner perimeter 13b of the plates 16b. Such welds 24 may comprise tack welds spaced intermittently along the inner perimeter 13b of the plates 16b or continuous welds along the inner perimeter 13b of the plates 16b. While not shown, and as long as they do not interfere with the sliding of the separator clutch plate 14b within the clutch housing (not shown) , such welds could also naturally comprise tack welds or continuous welds along the outside perimeter lib of the plates 16b or any combination of welds along both the outside perimeter lib and the inner perimeter 13b.

Figure 5, which is a section taken along line 5-5 in Figure 1, shows the structure of a separator clutch plate 14c which is substantially identical to the embodiment shown in Figure 2 except that the thinner plates 16c are connected together through the use of another type of weld; a laser weld 26. When used in such a manner, the laser welds may be keyholed, and the depth of penetration indicated by the letter "K" on Figure 5 may be any dimension deemed sufficient or desirable. As shown in Figure 5, the laser welds 26 may be located between adjacent plates 16c along the outside perimeter lie of the thinner plates 16c. Such laser welds may comprise tack welds spaced intermittently along the outside perimeter lie of the thinner plates 16c or a continuous weld along the outer perimeter lie of the thinner plates 16c. Of course, the location of such laser welds are a matter of design choice and may alternatively be located along the inner perimeter 13c of the thinner plates 16c or any combination of such welds could be used along both the inner perimeter 13c and the outside perimeter lie.

Figure 6 shows a typical perimeter configuration of a clutch plate 50 having an outside perimeter 51 and an inner perimeter 52 which defines internal splines 53. In the embodiment shown, friction material 54 having an overall circular configuration has been bonded to the side of the clutch plate 50. Such friction material 54 may comprise any suitable material and oftentimes is cellulose based. The friction material 54 shown are comprised of four separate pieces each having a male end 55 and a female end 56 such that the pieces may be interlocked to form the circular friction material 54 as shown and which may be bonded to the clutch plate 50 using any appropriate bonding agent such as a phenolic based adhesive. While a variety of friction materials and bonding agents are appropriate, because such friction materials and bonding agents are generally known in the art, they will not be discussed in further detail here.

Figure 7, which is a section taken along line 7-7 in Figure 6, shows the structure of a clutch friction clutch plate 60 made in accordance with this invention. As can be seen, the friction clutch plate 60 comprises two or more thinner plates, in this case two such thinner plates 62, which are connected together through the use of mechanical stakes 64, such as those already described regarding the embodiment shown in Figure 2. While not required, the mechanical stakes 64 are preferably located in the area of the interior splines 53 in order to avoid interference with the normal operation of the clutch assembly. Referring to Figure 6, the mechanical stakes 64 may be located approximately at points in the splines indicated by the letter "Z.^M As shown in this embodiment, the friction clutch plate 60 also has friction material 54 bonded to both sides.

Figure 8, which is a section taken along line 8-8 in Figure 6, shows the structure of a friction clutch plate 60a which is substantially identical to the embodiment shown in Figure 7 except that the two thinner plates 62a are connected together through the use of rivet pins 66. The rivet pins 66, which may or may not have heads 68a on one end, are inserted through holes in the thinner plates 62a and then upset or cold headed, as already described regarding the embodiment shown in Figure 3, so as to form a new second head 68b on the opposite end. The rivet pins 66 are preferably located in the area of the inner splines 53. Referring to Figure 6, the rivet pins 66 may be located approximately at points on the splines indicated by the letter "Z."

Figure 9, which is a section taken along line 9-9 in Figure 6, shows the structure of a friction clutch plate 60b which is substantially identical to the embodiment shown in Figure 7 except that the thinner plates 62b are connected together through the use of welds 70. As shown in Figure 9, the welds 70 may be located between adjacent plates 62b along the outside perimeter 51b of the plates 62b. Such welds 70 may comprise tack welds spaced intermittently along the outside perimeter 51b of the plates 62b or continuous welds along the outside perimeter 51b of the plates 62b. While not shown, and as long as they do not interfere with the sliding of the friction clutch plate 60b along a clutch shaft (not shown) or hub assembly (not shown) , such welds could alternatively comprise tack welds or continuous welds along the inner perimeter 52b of the plates 56b or any combination of welds along both the inner perimeter 52b and the outside perimeter 51b.

Figure 10, which is a section taken along line 10-10 in Figure 6, shows the structure of a friction clutch plate 60c which is substantially identical to the embodiment shown in Figure 7 except that the thinner plates 62c are connected together through the use of laser welds 72. When used in such a manner, the laser welds may be keyholed, and the depth of penetration indicated by the letter "K" on Figure 10 may be any dimension deemed sufficient or desirable. As shown in Figure 10, the laser welds 72 may be located between adjacent plates 60b along the outside perimeter 51c of the plates 62c. Such laser welds 72 may comprise tack welds spaced intermittently along the outside perimeter 51c of the plates 62c or continuous welds along the outside perimeter 51c of the plates 62c. Alternatively, such welds could also be located intermittently or continuously along the inner perimeter 52c of the plates 62c or any combination of such welds could be used along both the inner perimeter 52c and outside perimeter 51c of the thinner plates 62c.

Figure 11, which is a section taken along line 11-11 in Figure 6, shows the structure of a friction clutch plate 60d which is substantially identical to the embodiment shown in Figure 10 except that only one of the two thinner plates 62d has friction material 54d bonded to one side. Such a friction plate 60d would typically be used in a location where the friction material surface is only required on one side, i.e., the endmost clutch plate in a clutch assembly. Alternatively, such a friction plate 60d could be used in an application where friction material is bonded to one side of each of the alternating plates within a clutch assembly. For example, the friction clutch plate 60d shown in Figure 11 could be alternated with the friction clutch plate 156a shown in Figure 19. Such a design choice could naturally be used with any of the embodiments shown or with other embodiments not shown.

Figure 12, which is a section taken along line

12-12 in Figure 6, shows the structure of a friction clutch plate 60e which is similar to the embodiment shown in Figure 10 except that three thinner plates 62e are connected together through the use of laser welds 74. A design choice could also be made to use more than three thinner plates and such thinner plates could be connected together in any manner or any combination of manners. In such cases where the number of thinner plates forming a friction plate exceeds two, the one or more thinner plates sandwiched between the two outer thinner plates will not have friction material bonded to them.

Figure 13, which is a section taken along line 13-13 in Figure 1, shows the structure of a separator clutch plate 14d which is similar to the embodiment shown in Figure 4 except that only two thinner plates 16d and 16d' have been used and at least one of the thinner plates 16d' has manufactured hemispherical protrusions 76 located on the side of the thinner plate 16d' located adjacent the other thinner plate 16d. While the two plates 16d and 16d' may be connected in any suitable manner, they have been shown in this embodiment as being connected via a weld 78 located between the adjacent plates 16d and 16d' along the inner perimeter 13d.

Similarly, Figure 14, which is a section taken along line 14-14 in Figure 6, shows the structure of a friction clutch plate 60f which is similar to the embodiment shown in Figure 9 except that at least one of the thinner plates 62f* has manufactured hemispherical protrusions 80 located on the side of the thinner plate 62f located adjacent the other thinner plate 62f. While the two plates 62f and 62f may be connected in any suitable manner, they have been shown in this embodiment as being connected via a weld 82 located between the adjacent plates 62f and 62f along the outside perimeter 51f.

The protrusions shown in Figures 13 and 14 keep the two plates 16d and 16d', or 62f and 62f, separated, thereby allowing fluid to flow between the plates and facilitate cooling. Such protrusions 76 may be stamped into the plate 62f* or may be formed in any other method known in the art.

The variety of protrusions which can be used to separate the two or more thinner plates used to make a clutch plate in accordance with this invention are unlimited. Such protrusions are not limited to the hemispherical shaped disclosed and may be located anywhere on the thinner plates deemed appropriate. For example, a variety of such protrusions and locations are disclosed in the co-pending U.S. patent application entitled "Clutch Plate" filed on December 9, 1994, having Serial No. 352,602, and hereby incorporated by reference in its entirety. As long as the two or more thinner plates making up the clutch plate are connected together, any of the protrusion configurations shown in the U.S. patent application, Serial No. 352,602, or any infinite variety of configurations not shown, could be used in the manufacture of such clutch plates.

Figure 15, which is a section taken along line

15-15 in Figure 1, shows the structure of a separator clutch plate 14e which is similar to the embodiment shown in Figure 5 except that only two thinner plates 16e have been used, each formed by the punch and die method of manufacture. The deformations resulting from the punch and die method of manufacture have been exaggerated in this Figure 15 for illustrative purposes. As a result of the punch and die method of manufacture, and as more fully explained in the U.S. patent application, Serial No. 352,602, incorporated by reference in its entirety, the outside perimeter lie of each thinner plate 16g has a circumferential radiused portion 90, a circumferential shear surface 92 adjacent the radiused portion 90, and a circumferential die break surface 94 adjacent the circumferential shear surface 92. Likewise, the inner perimeter 13e of each thinner plate 16e has a circumferential radiused portion 100, a circumferential shear surface 102 adjacent the radiused portion 100, and a circumferential die break surface 104 adjacent the circumferential shear surface 102. While the two thinner plates 16e may be connected in any suitable manner, they have been shown in this embodiment as being connected via a laser weld 108. Figure 16, which is a section taken along line 16-16 in Figure 6, shows the structure of a friction clutch plate 60g which is similar to the embodiment shown in Figure 10. In this embodiment, friction plate 60g is formed from two thinner plates 62g, each of which has been formed by the punch and die method of manufacture. The deformations resulting from the punch and die method of manufacture have been exaggerated in this Figure 16 for illustrative purposes. As a result of the punch and die method of manufacture, and as more fully explained in the U.S. patent application, Serial No. 352,602, incorporated by reference, the outside perimeter 51g of each thinner plate 62g has a circumferential radiused portion 110, a circumferential shear surface 112 adjacent the radiused portion 80, and a circumferential die break surface 114 adjacent the circumferential shear surface 112. Likewise, the inner perimeter 52g of each thinner plate 62g has a circumferential radiused portion 120, a circumferential shear surface 122 adjacent the radiused portion 120, and a circumferential die break surface 124 adjacent the circumferential shear surface 122. While the two thinner plates 62g may be connected in any suitable manner, they have been shown in this embodiment as being connected via a laser weld 126.

As set forth in U.S. patent application Serial θi 352,602 incorporated by reference, the sliding of the resultant clutch plates 14e and 60g within the clutch housing and along the clutch shaft or hub assembly will be facilitated by the symmetrically located circumferential shear bearing surfaces 92 and 102, or 112 and 122, respectively. The sliding of the clutch plates 14e and 60g will be further facilitated by the radiused portion 90 and 100, or 110 and 120, respectively, located circumferentially at the outside perimeter of the clutch plates 14e and 60g. Furthermore, lubricating/cooling fluid within the transmission may collect in the pocket formed by the adjacent die break surfaces 94 and 104, or 114 and 124, respectively, which will aid in allowing the friction plate to slide properly within the clutch housing.

Of course, the thinner plates 62g could be oriented in any manner relative to each other before being connected. For example, the circumferential shear bearing surfaces could alternatively be located adjacent to each other or a circumferential shear bearing surface could be located adjacent a circumferential die break surface. Other such combinations would include, without limitation, those shown in U.S. patent application Serial No. 352,602 incorporated by reference, or any other combination, as long as the thinner plates are connected together. The possible variations are endless, depending upon the orientation and number of thinner plates used. As an additional benefit, as set forth in U.S. patent application Serial No. 352,652 incorporated by reference, the deformation resulting from the punch and die method of manufacture may serve to separate the thinner plates slightly, thereby facilitating the flow of fluids between the plates so as to cool them and prevent hot spotting.

In view of the fact that using the punch and die method to manufacture such separator and friction plates is well known in the art, no further discussion of that method of manufacture will be undertaken here.

While such plates may be manufactured from SAE 1020 steel, other grades, such as without limitation SAE 1035 and SAE 1050 steel, are also suitable. Figure 17 shows a typical perimeter configuration of a clutch plate 150 having an outside perimeter 151 which defines external splines 152 and an inner perimeter 153. In the embodiment shown, friction material 154 having an overall circular configuration has been bonded to the side of the clutch plate 150. As already discussed, because such friction materials and bonding agents are generally known in the art, they will not be discussed in further detail here.

Figure 18, which is a section taken along line

18-18 in Figure 17, shows the structure of a friction clutch plate 156 made in accordance with this invention. As can be seen, the friction clutch plate 156 comprises two or more thinner plates, in this case four such thinner plates 158, which are connected together through the use of laser welds 160. Such laser welds are generally known in the art and will not be discussed in further detail here. As shown in this embodiment, the friction clutch plate 156 has friction material 154 bonded to both sides of the friction clutch plate 156.

Figure 19, which is a section taken along line 19-19 in Figure 17, shows the structure of a friction clutch plate 156a which is substantially identical to the embodiment shown in Figure 21 except that only one of the two thinner plates 158a has friction material 154a bonded to one side. Such a friction plate 156a would typically be used in a location where the friction material surface is only required on one side, i.e., the end most clutch plate in a clutch assembly. Alternatively, such a friction clutch plate 156a could be used in an application where friction material is bonded to one side of each of the alternating plates within a clutch assembly. For example, the friction clutch plate 156a shown in Figure 19 could be alternated with the friction clutch plate 60b shown in Figure 11.

Figure 20 shows a typical perimeter configuration of a clutch plate 170 having an outside perimeter 171 and an inner perimeter 172 which defines internal splines 173.

Figure 21, which is a section taken along line 21-21 in Figure 20, shows the structure of a clutch separator plate 174 made in accordance with this invention. As can be seen, the separator clutch plate 174 comprises two or more thinner plates, in this case four such thinner plates 176, which are connected together through the use of laser welds 178.

It is also contemplated that the perimeter configurations of adjoining thinner plates need not match. In fact, in order to save on material, it is possible to eliminate the splines from a number of adjoining thinner plates so as to save material. Examples have been shown in Figures 22 and 23.

Figure 22, which is a section taken along line

22-22 in Figure 1, shows the structure of a clutch separator plate 180 made in accordance with this invention. As can be seen, the clutch separator plate 180 comprises two or more thinner plates, in this case four such thinner plates 182 and 184, which are connected together through the use of laser welds 186. In order to save on material, splines 12 have been eliminated from the two innermost thinner plates 184.

Similarly, Figure 23, which is a section taken along line 23-23 in Figure 6, shows a structure of a friction clutch plate 190 made in accordance with this invention. The friction clutch plate 190 comprises two or more thinner plates, in this case two such thinner plates 192 and 194, which are connected together through the use of laser welds 196. Splines 53 have been eliminated from the one thinner plate 194. In addition to the embodiments shown in Figures 22 and 23, splines may be eliminated in any desired pattern.

Because all of the clutch plates claimed comprise two or more thinner plates connected together, vibration of the clutch plate during use is dampened. Accordingly, the clutch plates of this invention will decrease the shudder and wear which normally occurs. In fact, each of the embodiments shown illustrates the preference that the adjacent sides of the thinner plates be at least partially unconnected to each other. More specifically, if the sides are at least partially unconnected, the vibration of each thinner plate will tend to be dampened by its unconnected contact with an adjacent thinner plate and vice versa. By connecting the thinner plates together, the thinner plates cannot move or rotate relative to each other which might otherwise cause wear. Accordingly, the preferred clutch plate of this invention reduces both shudder and wear.

Another advantage of this invention is that clutch plates may be made to much closer tolerances of flatness. When clutch plates are made, they typically have a very small set, i.e., a slight overall bow or curve. If such a clutch plate is made from two or more thinner plates, and if the configuration of the splines is such that the splines may be realigned while orientating by rotation one plate a number of degrees relative to the other plate, the inherent set of one plate can be used to oppose and cancel the inherent set in another plate. In other words, instead of connecting the thinner plates together in such a way that they "spoon," one of the thinner plates is turned around and then rotated to oppose the set of the other thinner plate before the thin plates are fastened together. In this way, the inherent sets or curvatures would oppose and be canceled to some extent.

This has been illustrated in Figures 24, 25 and 26 which are sections taken along lines 24-24, 25-25 and 26-26, respectively, in Figures 1 and 6. Figures 24 and 25 show two thinner plates 90 in which the inherent sets have been exaggerated for illustrative purposes. In Figures 24 and 25, the two thinner plates 90 have been oriented by rotation and aligned such that the set of one thinner plate opposes the set of the other thinner plate. Figure 26 illustrates the relatively "flat" clutch plate which results from connecting the two thinner plates 90 when the sets are in opposition prior to connection as shown in Figures 24 or 25. While only two thinner plates are shown in this embodiment, more than two could obviously be used. However, to obtain the best results, it is preferred that an even number of thinner plates be used, and that the paired opposing thinner plates have an approximately equal thickness so that the inherent set of one thinner plate will not override the inherent set of the opposing thinner plate.

By being able to make flatter clutch plates, the resulting frictional forces located between adjacent plates are not concentrated at the apex of such a set, but are instead distributed evenly between adjacent and engaging clutch plates. This will further reduce vibration and wear.

The thicknesses of the thinner plates friction materials as shown in the embodiment figures have been exaggerated for illustrative purposes. The thicknesses of the thinner plates used, and the friction material, and the overall clutch plate, may be varied as desired for particular applications.

Furthermore, any number of two or more thinner plates may be used and it is contemplated that any of the connections or connection methods disclosed may be used in any of the embodiments disclosed. In fact, any variety or combination of connections or connection methods, whether disclosed or not, may be used in the construction of any one clutch plate. It is also contemplated that thinner plates made by different manufacturing methods, such as one thinner plate made by the punch and die method of manufacture and one plate made by fine blanking, may be used together in the formation of one clutch plate.

Accordingly, while particular embodiments of the invention have been illustrated and described, it will be obvious to those skilled in the art that various changes and modifications, many of which have not been disclosed or described, may be made without departing from the invention. It is intended that the following claims cover all such modifications and all equivalents that fall within the true spirit and scope of this invention.

Claims

What Is Claimed Is:

1. A clutch plate comprising a first plate and at least a second plate, the first plate defining a first spline and having a first plate side and the second plate having a second plate side, and the first plate and second plate being connected together such that the first plate side is adjacent to and at least partially unconnected to the second plate side.

2. A clutch plate as defined in claim 1 wherein the second plate has a second spline.

3. A clutch plate as defined in claim 2 wherein the connection is between the first plate and second plate in the area of the first spline and the second spline.

4. A clutch plate as defined in claim 1 wherein the first plate side of the first plate defines a first protrusion such that the first plate and the second plate will be spaced apart by the first protrusion when connected together.

5. A clutch plate as defined in claim 1 wherein the first plate and the second plate are manufactured by the punch and die method.

6. A clutch plate as defined in claim 5 wherein the first plate has a first circumferential shear surface and a first circumferential die break and the second plate has a second circumferential shear surface and a second circumferential die break, the first circumferential die break being located adjacent the second circumferential die break.

7. A clutch plate as defined in claim 1 wherein the first plate has a first set and the second plate has a second set and the first plate is oriented to the second plate and connected to the second plate such that the first set opposes the second set.

8. A clutch plate as defined in claim 1 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to the first exterior side.

9. A clutch plate as defined in claim 1 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to both the first exterior side and second exterior side.

10. A clutch plate comprising a first metallic plate and at least a second metallic plate, the first plate defining a first spline and having a first plate side, the second plate having a second plate side and a second spline, the first plate and the second plate being connected together such that the first side is adjacent the second side.

11. A clutch plate as defined in claim 10 wherein the second plate defines a second spline.

12. A clutch plate as defined in claim 11 wherein the connection between the first plate and second plate is located in the area of the first spline and the second spline.

13. A clutch plate as defined in claim 10 wherein the first plate side of the first plate defines a first protrusion such that the first plate and the second plate will be spaced apart by the first protrusion when connected together.

14. A clutch plate as defined in claim 10 wherein the first plate and the second plate are manufactured by the punch and die method.

15. A clutch plate as defined in claim 14 wherein the first plate has a first circumferential shear surface and a first circumferential die break and the second plate has a second circumferential shear surface in a second circumferential die break, the first circumferential die break being located adjacent the second circumferential die break.

16. A clutch plate as defined in claim 10 wherein the first plate has a first set and the second plate has a second set and the first plate is oriented to the second plate and connected to the second plate such that the first set opposes the second set.

17. A clutch plate as defined in claim 10 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to the first exterior side.

18. A clutch plate as defined in claim 10 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to both the first exterior side and second exterior side.

19. A clutch plate comprising a first plate and a second plate, the first plate having a first plate side and the second plate having a second plate side, the first plate having a first outside perimeter defining a first spline, and the first plate and the second plate being connected together such that the first plate side of the first plate is adjacent to and at least partially unconnected to the second plate side of the second plate.

20. A clutch plate as defined in claim 19 wherein the second plate has a second outside perimeter defining a second spline.

21. A clutch plate as defined in claim 20 wherein the connector is located in the area of the first spline and the second spline.

22. A clutch plate as defined in claim 19 wherein the first plate has a first plate side which defines a first protrusion located adjacent the second plate such that the first plate and the second plate will be spaced apart by the first protrusion.

23. A clutch plate as defined in claim 19 wherein the first plate and the second plate are manufactured by the punch and die method.

24. A clutch plate as defined in claim 23 wherein the first plate has a first circumferential shear surface and a first circumferential die break and the second plate has a second circumferential shear surface in a second circumferential die break, the first circumferential die break being located adjacent the second circumferential die break.

25. A clutch plate as defined in claim 19 wherein the first plate has a first set and the second plate has a second set and the first plate is oriented to the second plate and connected to the second plate such that the first set opposes the second set.

26. A clutch plate as defined in claim 19 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to the first exterior side.

27. A clutch plate as defined in claim 19 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to both the first exterior side and second exterior side.

28. A clutch plate as defined in claim 19 wherein the configurations of the first and second splines are substantially identical such that the first and second splines are aligned with the first plate is connected to the second plate.

29. A clutch plate comprising a first plate and a second plate, the first plate having a first plate side and the second plate having a second plate side, the first plate having a first inner perimeter defining a first spline and the first plate and the second plate being connected together such that the first plate side of the first plate is adjacent to and at least partially unconnected to the second plate side of the second plate.

30. A clutch plate as defined in claim 29 wherein the second plate has a second inside perimeter defining a second spline.

31. A clutch plate as defined in claim 30 wherein the connector is located in the area of the first spline and the second spline.

32. A clutch plate as defined in claim 30 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to the first exterior side.

33. A clutch plate as defined in claim 30 wherein the clutch plate has a first exterior side and a second exterior side and friction material is bonded to both the first exterior side and second exterior side.

34. A clutch plate as defined in claim 30 wherein the first side of the first plate defines a first protrusion located adjacent the second plate such that the first plate and the second plate will be spaced apart by the first protrusion.

35. A clutch plate as defined in claim 30 wherein the first plate and the second plate are manufactured by the punch and die method.

36. A clutch plate as defined in claim 35 wherein the first plate has a first circumferential shear surface and a first circumferential die break and the second plate has a second circumferential shear surface in a second circumferential die break, the first circumferential die break being located adjacent the second circumferential die break.

37. A clutch plate as defined in claim 30 wherein the first plate has a first set and the second plate has a second set and the first plate is oriented to the second plate and connected to the second plate such that the first set opposes the second set.

38. A clutch plate as defined in claim 30 wherein the configurations of the first and second splines are substantially identical such that the first and second splines are aligned with the first plate is connected to the second plate.