Field

[001] This application relates to friction discs and segments therefor comprising pucks of friction materials. The friction discs can be used in clutch applications.

Background

[002] Friction discs for clutches are typically integrated assemblies having a plate to integrate individual pads of friction material. Or, in the case of organic facings, friction discs can be an integrated disc of material. The assembly process can be inefficient and can result in wasted time and resources.

SUMMARY

[003] The methods disclosed herein overcome the above disadvantages and improves the art by way of a friction pad segment comprises a puck of friction material for gripping a surface. A segment plate comprises first fingers on a first end and second fingers on a second end. The first fingers are shaped complementarily to the second fingers so as to intercalate the second fingers when the segment plate is cleaved along the first plane.

[004] A cushion assembly for a clutch can comprise a perforated disc comprising a first side and a second side. A pattern of perforations can be included for flexing the disc when the disc is compressed. A first pattern of coupling locations can comprise first coupling locations and second coupling locations. A first friction pad segment can be coupled to the first side of the perforated disc. The first friction pad segment can comprise a first puck of friction material for gripping a surface, the first puck comprising first puck holes through the friction material. A first segment plate can comprise first fingers on a first end and second fingers on a second end. A second friction pad segment can be coupled to the second side of the perforated disc. The second friction pad segment can comprise a second puck of friction material for gripping a surface, the second puck comprising second puck holes through the friction material. A second segment plate can comprise first fingers on a first end and second fingers on a second end. The first fingers of the second friction pad segment are coupled to the first coupling locations and are coupled to the first puck holes of the first friction pad segment.

[005] A cushion assembly can further comprise a third friction pad segment coupled to the second side of the perforated disc. The third friction pad segment can comprise a third puck of friction material and a third segment plate comprising first fingers on a first end and second fingers on a second end. The second fingers of the third friction pad segment can be intercalated with the first fingers of the second friction pad segment. And, the second fingers of the third friction pad segment can be coupled at the first coupling locations and at the first puck holes.

[006] A cushion assembly for a clutch can alternatively comprise a perforated disc comprising a first side and a second side. A pattern of perforations for flexing the disc when the disc is compressed can be included. Perforations can comprise a first pattern of coupling locations comprising first coupling locations and second coupling locations. A first friction pad segment can be coupled to the first side of the perforated disc. The first friction pad segment can comprise a first puck of friction material for gripping a surface and a first segment plate comprising first fingers on a first end and second fingers on a second end. The second fingers can be coupled to the first coupling locations. A second friction pad segment can be coupled to the first side of the perforated disc. The second friction pad segment can comprise a second puck of friction material for gripping a surface and a second segment plate comprising first fingers on a first end and second fingers on a second end. The first fingers can be coupled to the first coupling locations. The second fingers of the first segment plate are shaped complementarily to the first fingers of the second segment plate so as to intercalate.

[007] The friction pad segments and cushion assemblies can be configured to form an aspect of a clutch. For example, the friction pad segments can be assembled and attached to a driven disk assembly of a damped clutch. Other clutch configurations can also be contemplated, such as undamped or direct-acting clutch discs.

[008] As another alternative aspect, a clutch assembly can comprise a driven disk assembly. A perforated disk can be coupled to the driven disk assembly. A plurality of friction pad segments can be intercalated and coupled to the perforated disc. Each of the plurality of friction pad segments can comprise a puck of friction material for gripping a surface and a segment plate comprising first fingers on a first end and second fingers on a second end. The plurality of friction pad segments can be intercalated by placing the plurality of friction pad segments serially adjacent to one another and by placing respective second fingers of the plurality of segment plates in complementarily shaped respective first fingers of the plurality of segment plates.

[009] Additional objects and advantages will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the disclosure. The objects and advantages will also be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[010] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the claimed invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[011] Figure 1 is a view of a friction pad segment comprising a puck of friction material.

[012] Figure 2 is a view of a cushion assembly comprising an assembly of friction pad segments.

[013] Figure 3 is a section view of a portion of Figure 2.

[014] Figure 4 is a view of a perforated disc.

[015] Figure 5 is a side view of a cushion assembly.

[016] Figure 6A is a front view of a clutch assembly.

[017] Figure 6B is a cross-section view of a clutch assembly.

DETAILED DESCRIPTION

[018] Reference will now be made in detail to the examples which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers will be used throughout the drawings to refer to the same or like parts. Directional references such as "left" and "right" are for ease of reference to the figures. Rivets and rivet holes are described as means for affixing the friction pad segments to form a cushion assembly. It is contemplated that equivalents to rivets be within the scope of the claimed invention. Coupler equivalents include but are not limited to rivets, brazing, welding, threaded couplers, crimped couplers, nut and bolt combinations, and the like.

[019] A friction disc for a clutch must be sufficiently rigid for its

environmental use, but it is desired to lower the inertia of a friction disc as much as possible so as to require less energy to actuate the friction disc. By using the multiple friction pad segment design disclosed herein, a friction disc has a lower inertia because a rigid backer plate can be eliminated by intercalating fingers of adjoining friction pad segments. This can eliminate a 2 mm thick rigid disc from the assembly. Designing the fingers to extend from the friction pad segments to intercalate with adjoining friction pad segments provides adequate rigidity to eliminate the backer plate from a driven disc assembly (DDA). Eliminating the backer plate reduces inertia of the assembled friction disc, making the friction disc applicable to a wider variety of gearboxes.

[020] A friction pad segment is shown in Figure 1. It comprises a puck 500 of friction material for gripping a surface. The friction material can be, for example, a ceramic material such as used in a transmission clutch. Other materials can also be used based on application of the friction pad segment. Making a friction pad segment 150 of a small size makes it easier to switch between friction materials based on application, increasing choice of friction materials. More characteristics and materials are available. The disclosed friction pad segments can enable full disc assemblies, which have only a single friction material on the whole disc. But, by the pucks 500 being in small segments, it is easier to manufacture friction discs having different friction material grades on the same friction disc assembly. This contrasts the options of the full disc assemblies and it also permits cushion assemblies offering different characteristics on each side thereof.

[021] A segment plate 150 comprises first fingers 210, 211 on a first end and second fingers 1 10, 11 1 on a second end. The first fingers 210, 211 are shaped complementarily to the second fingers 110, 11 1 so as to intercalate the second fingers when the segment plate is cleaved along a first plane PL First plane P1 can bisect the friction pad segment between the first fingers on one side and the second fingers on the other side.

[022] The puck 500 can comprise a shape generally chosen for heat dissipation and coupling strength. The illustrated puck shape is "8-shaped," though other shapes such as rectangles, trapezoids, etc. can be substituted. The puck 500 comprises first holes 501 , 503 and second holes 502, 504 through the friction material.

[023] The puck 500 further comprises a first axis A-A extending for a height, which can be considered a longitudinal axis or a midline. The first plane P1 intersects the first axis A-A and extends for a width through the friction pad segment. A second axis B-B can be perpendicular to the first axis A-A. The second axis B-B can extend for a length. The first holes 501 , 503 and the second holes 502, 504 through the puck 500 can be intersected by the first plane P1 to be "in-line," as drawn. The puck holes 501-504 can be bisected by the first axis A-A. Or, deviations can be configured so that the puck holes are not perfectly bisected by the axis A-A. Having at least a portion of each puck hole intersected by the first plane P1 facilitates easy manufacture. There puck holes 501-504 can be formed as relief holes in the middle of the friction material to accommodate rivet heads or rivet ends or equivalent couplers and to prevent interference with the rivets or other couplers.

[024] Depending on the coupler chosen, the segment plate can comprise modifications for coupling. In the illustrated example, coupler locations comprise coupler holes 301-304 through the segment plate. The coupler holes 301-304 can be configured to receive rivets 321-324. The coupler holes 301-304 can align with the first puck holes 501 , 503 and the second puck holes 502, 504 so that the coupler can be used without marring the friction material. As drawn, the coupling locations are aligned to intersect a plane and can be considered "in-line."

[025] The first fingers 210, 21 1 can comprise first finger holes 201 , 202 aligned along a first finger axis C-C. The second fingers 1 10, 11 1 can comprise second finger holes 101 , 102 aligned along a second finger axis D-D. The first finger holes 201 , 202 of the first fingers are configured to align with the first puck holes 501 , 503 along the first plane P1 of the friction material when the segment plate 150 is cleaved along the first plane P1 and the cleaved portion of the segment plate is inverted. Likewise, the second finger holes 101 , 102 are configured to align with the second puck holes 502, 504 when the segment plate 150 is cleaved along the first plane P1 and the cleaved portion of the segment plate is inverted.

[026] A cushion assembly can be formed, as shown in Figure 2. A perforated disc 450, such as shown in Figure 4, can form a central cushion for the cushion assembly. The perforated disc 450 can be, for example, a stamped sheet material. It can be formed with blades 451. When the friction pad segments are arranged serially around the perforated disc 450, the first and second fingers of adjacent friction pad segments can be intercalated at the cushion blades 451. Then, heat expansion is enabled and warpage is lessened. The friction pad segments can be aligned so as not to be constrained to the cushion blades 451. This can delay cushion (perforated disc) heating. The friction pad segments can expand

independently, and are more robust against warping.

[027] In one example, a cushioned ceramic driven disc assembly comprises a cushioned disc (perforated disc) having two sets of riveting holes of four holes each. The sets of riveting holes can be arranged in rows to form in-line coupler holes. One set of riveting holes 401-404 is aligned to face, for example, a flywheel side of the DDA. Another set of riveting holes 411-414 are aligned to face, for example, a gearbox side of the DDA. As drawn, there are 9 friction pad segments on the flywheel side (first side 461) and 9 friction pad segments on the gearbox side (second side 462). Adjacent friction pad segments are intercalated and riveted at puck holes 501-504 & 531-534 through the puck of the friction material. Each friction pad segment can be supported by four rivets 321-324 or 331-334 through respective puck holes. Each row of riveting holes in the example comprises 4 riveting holes, and the single row is used to rivet two adjacent friction pad segments to a perforated disc. For a two-sided cushion assembly, each row of riveting holes in the example comprises four riveting holes, and the single row is used to rivet two adjacent friction pad segments and an inverted friction pad segment to a perforated disc.

[028] The perforated disc 450 can be designed to comprise segments that are "wavy" to provide a cushion function. The perforated disc 450 can be stamped, pressed or otherwise bent to provide the "waviness." The blades 451 can be formed by including slots 430 at intervals around the perforated disc 450. The slots can comprise an aspect of the pattern of perforations. The slots 430 can comprise a longitudinal portion 431 that extends from top to bottom. A turn 432 can be included between the longitudinal portion 431 and a latitudinal portion 433. The blades 451 can flex and release heat due to the slots 430. The cushion life of the perforated disc 450 then tends to be higher since the it will have more even loading due to the gap that extends from top to bottom. This is an improvement over the bigger slots on prior art full disc assemblies. The prior art slots on full disc assemblies cannot go from top to bottom without cleaving the disc.

[029] The puck 500, or friction material area, is not in contact with the perforated disc (cushion disc) while the friction material is not compressed. This can reduce the heating of the cushion disc the puck 500. The separation can preserve the cushion function for a longer time. At least one additional heat release slot 405 can also be included on each blade 451 , as an additional example of a pattern of perforations. Then, at least one portion of the pattern of perforations in the perforated disc 450 releases heat. The puck comprising the friction material can be aligned with at least one portion that releases heat, including the heat release slot 405 or slot 430.

[030] A cushion assembly for a clutch can comprise a cushion disc such as perforated disc 450 and can comprise a first side 461 and a second side 462. A pattern of perforations, such as slots 430 or rivet holes 401-404, 41 1-412, can be included for flexing the disc when the disc is compressed. A first pattern of coupling locations can comprise first coupling locations 401-404 and second coupling locations 411-414. A first friction pad segment can be coupled to the first side 461 of the perforated disc 450.

[031] The plurality of friction pad segments coupled to the perforated disc 450 can be identical to that shown in Figure 1 and numbering of identical parts is limited to avoid obfuscating the aspects drawn. Using identical parts for the entire friction disc reduces the complexity of stocking parts and minimizes waste. Such benefits double for the cushion assembly of Figure 5 because the identical parts are usable for both friction discs for both sides of the cushion assembly. The first friction pad segment can comprise a first puck 551 of friction material for gripping a surface, the first puck comprising first puck holes 531-534 through the friction material. A first segment plate 151 can comprise first fingers on a first end and second fingers on a second end. Another friction pad segment can be coupled to the second side 462 of the perforated disc 450. The second friction pad segment can comprise another puck 500 of friction material for gripping a surface and puck holes through the friction material. Another segment plate 150 can comprise first fingers 210, 211 on a first end and second fingers 110, 1 11 on a second end. The first fingers of the another friction pad segment are coupled to the first coupling locations and are coupled to the first puck holes of the first friction pad segment as by rivets 341 , 343.

[032] A cushion assembly can further comprise a third friction pad segment coupled to the second side 462 of the perforated disc 450. The third friction pad segment can comprise a third puck 553 of friction material and a third segment plate 153 comprising first fingers on a first end and second fingers on a second end. The second fingers of the third friction pad segment can be intercalated with the first fingers of the another friction pad segment. And, the second fingers of the third friction pad segment can be coupled at the first coupling locations and at first puck holes as by rivets 342, 344.

[033] A cushion assembly for a clutch can alternatively comprise a perforated disc 450 comprising a first side 461 and a second side 462. A pattern of perforations for flexing the disc when the disc is compressed can be included.

Perforations can comprise a first pattern of coupling locations comprising first coupling locations 401-404 and second coupling locations 411-414. A first friction pad segment can be coupled to the first side 461 of the perforated disc 450. The first friction pad segment can comprise a first puck 551 of friction material for gripping a surface and a first segment plate 151 comprising first fingers on a first end and second fingers on a second end. The second fingers can be coupled to first coupling locations 401 , 403. A second friction pad segment can be coupled to the first side 461 of the perforated disc 450. The second friction pad segment can comprise a second puck 552 of friction material for gripping a surface and a second segment plate 152 comprising first fingers on a first end and second fingers on a second end. The first fingers of the second segment plate can be coupled to first coupling locations 402, 404. The second fingers of the first segment plate are shaped complementarily to the first fingers of the second segment plate so as to intercalate.

[034] Rivets 334, 332 can be couplers for securing the first fingers 1521 , 1522 of the second segment plate 152 to the first coupling locations 401 , 403 and to puck holes 534, 532 of the third puck 553 of the third friction pad segment. Rivets 333, 331 can be couplers for securing second fingers 1511 , 1512 of the first segment plate 151 to coupling locations 402, 404 and to puck holes 533, 531 of the third friction pad segment. A single coupler can secure three parts together, which reduces the number of couplers and coupling steps.

[035] Comparing Figure 6A and 2, it can be seen that the rivets 361-364 used to couple intercalated first fingers of the third segment plate with second fingers of an adjacent segment plate are also used to couple in the puck holes of second puck 552. Rivets 341-344 use to couple intercalated second fingers of the third segment plate with first fingers of an adjacent segment plate are also used to couple in the puck holes of first puck 551.

[036] When using an in-line formulation for the first and second coupling locations 401-404 & 41 1-414 it is possible to align the plurality of friction pad segments along parallel axis. For example, axis C1-C1 bisecting the corresponding first finger holes of the first segment plate 151 can co-extend with axis D-D bisecting second finger holes 101 , 102 of the segment plate 150 that is adjacent the first segment plate 151. Axis D1-D1 bisecting corresponding second finger holes on first segment plate 151 can co-extend with axis C2-C2 bisecting corresponding first finger holes on second segment plate 152. An axis A3-A3 bisecting third puck holes in puck 553 can be parallel to the co-extending axis C2-C2 and D1-D1. A plane can then pass through the parallel and co-extending axis (through A3-A3, C2-C2 and D1-D1) to make fingers of the intercalated first and second segment plates co- planar with a puck of a third segment plate.

[037] A circuitous gap G can be formed between each of the friction pad segments, including between the third friction pad segment and the second friction pad segment. The perforated disc 450 can flex along the gap G. The gap G can follow the contour between two adjacent friction pad segments. This gap G allows for thermal expansion under severe conditions without creating distortion and without losing function. A prior art full disc cannot expand in this way. The disclosed design has a high thermal capacity and it can stand a high number of heat cycles due to the individual segments that can expand with more independence.

[038] The friction pad segments and cushion assemblies can be configured to form an aspect of a clutch, as shown in Figures 6A & 6B. For example, the friction pad segments can be assembled and attached to a driven disk assembly of a damped clutch. Other clutch configurations can also be contemplated, such as undamped or direct-acting clutch discs. [039] A clutch assembly can comprise a driven disk assembly. A driven disk 900 can be housed between side plates 610, 620. Damper springs 660 can be affiliated with the driven disk assembly. Stack plates 910 can be adjacent the driven disk 900. A rivet 920 or other coupler can affix the side plates together. A predamper assembly 700 can optionally be included, including a predamper side plate 710 and damper springs 770. The driven disk assembly can comprise a hub 800 for mounting to an axle or the like. The clutch assembly can be actuated to couple torque. For example, torque can pass from a flywheel of an engine to a transmission. Other clutch applications are contemplated.

[040] The perforated disk 450 can be coupled to the driven disk assembly as by mounting holes 420 in tabs 420. A plurality of friction pad segments identical to those shown in Figure 1 can be intercalated and coupled to the perforated disc. Each of the plurality of friction pad segments can comprise a puck of friction material for gripping a surface and a segment plate comprising first fingers on a first end and second fingers on a second end. The plurality of friction pad segments can be intercalated by placing the plurality of friction pad segments serially adjacent to one another and by placing respective second fingers of the plurality of segment plates in complementarily shaped respective first fingers of the plurality of segment plates.

[041] A cushioned driven disc assembly comprising a ceramic friction pad according to the disclosure has significant lower tooling cost involved compared to prior full disc assemblies. The intercalated assembly gives to the whole assembly the characteristic of a full friction disc on each side.

[042] Other implementations will be apparent to those skilled in the art from consideration of the specification and practice of the examples disclosed herein.