CA1190872A - Fluid cooled clutch - Google Patents
Fluid cooled clutchInfo
- Publication number
- CA1190872A CA1190872A CA000438981A CA438981A CA1190872A CA 1190872 A CA1190872 A CA 1190872A CA 000438981 A CA000438981 A CA 000438981A CA 438981 A CA438981 A CA 438981A CA 1190872 A CA1190872 A CA 1190872A
- Authority
- CA
- Canada
- Prior art keywords
- clutch
- fluid
- material layer
- shaft
- assembly
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/66—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing specially adapted for continuously variable gearings
- F16H2061/6604—Special control features generally applicable to continuously variable gearings
- F16H2061/6618—Protecting CVTs against overload by limiting clutch capacity, e.g. torque fuse
Landscapes
- Transmissions By Endless Flexible Members (AREA)
Abstract
ABSTRACT
The present invention deals with a variable pulley transmission assembly operable between a prime mover and a driven means. The assembly includes input and output pulleys each with a movable sheave, where the pulleys are connected by a flexible belt, a fluid-actuated and fluid cooled starting clutch (16), a forward-reverse-neutral gear arrangement and a differential drive system connected to the driver means. The system also includes a control system to control the fluid actuated clutch (16) and the movable sheaves (68,152). The clutch includes a deeply grooved pattern (345) to provide adequate cooling with low pressure oil before its return to sump. This assembly provides a slippable clutch that acts analogously to a fuse under certain conditions to avoid excess loads to the belt means and also to provide lower operating pressure limits on the movable sheave maintaining belt tension. The clutch further provides a low end lugging limit slip to thereby avoid "torsionals"
being transmitted past the clutch. The invention likewise provides a continuously variable pulley (CVT) transmission that has a ratio range of 5.4 to 1,
The present invention deals with a variable pulley transmission assembly operable between a prime mover and a driven means. The assembly includes input and output pulleys each with a movable sheave, where the pulleys are connected by a flexible belt, a fluid-actuated and fluid cooled starting clutch (16), a forward-reverse-neutral gear arrangement and a differential drive system connected to the driver means. The system also includes a control system to control the fluid actuated clutch (16) and the movable sheaves (68,152). The clutch includes a deeply grooved pattern (345) to provide adequate cooling with low pressure oil before its return to sump. This assembly provides a slippable clutch that acts analogously to a fuse under certain conditions to avoid excess loads to the belt means and also to provide lower operating pressure limits on the movable sheave maintaining belt tension. The clutch further provides a low end lugging limit slip to thereby avoid "torsionals"
being transmitted past the clutch. The invention likewise provides a continuously variable pulley (CVT) transmission that has a ratio range of 5.4 to 1,
Description
This invention relates to a fluid cooled clutch.
This is a division of copending Canadian Patent Application Serial No~ 400,560, filed April 6, 1982.
Variable pulley transmission assemblies are known in the prior art and are comprlsed of variable sheave pulleys, a connecting belt means and a control means. In automotive applications it has been necessary to utilize hydrodynamic and/or clutch assemblies as starting devices. This same automotive application requires a means or method to effect a change of direction. It has been found that forward-reverse gear mechanisms having planetary gearing and sepaxate clutches cvuld perform such a task. Planetary gearing also provides a means to attain a desirable gear reduction. Alternatively, a change of direction could be accomplished with a reversal of the pulley rotation. This method of directional change, assuming low belt ratio, requires stopping pulley rotation and initiating motion of ~he drive train members in an oppo~
site direction. Further, a change of belt ratio when the pulleys are stopped requires that the belt be slid across the pulley faces causing wear on both the belt and the pulley surfaces, and requires a great deal of force to perform such a belt movement.
A var.iable pulley transmission assembly may be operable between a prime mover and a driven means. The assembly includes, in order, from the prime mover, a vibration damper, input and output movable sheave pulleys connected by a flexible belt~ a belt ratio control arrangement, a wet clutch, a forward-neutral-reverse gear arrangement and connecting elements to a drive means, generally a differen~
tial drive system with rin~ and pinion gear set. This apparatus is adaptable for use with an automobile where the engine is the prime mover and the final drive means is a dif:Eerenti.al-axle-wheel assembly.
mab/Jc ~^
87~
According to the present invention there is pro-vided a fluid cooled clutch including a generally annula.r laminated clutch disc assembly having an inner and an outer periphery which disc assembly includes a central d,isc with opposed surfaces, a resilient material layer af:Eixed to each surface and a friction material layer affi.xed to each resilient layer where each resilient layer is at least as thck as the friction material layer. A pattern of grooves is provided in the friction material layer, which grooves extend completely through the friction material layer and through substantially all of the resilient layer thus pro-viding a path for coolant fluid :Elow in the laminated struc-t.ure which is subst,antia',.ly greater than that of a grooved friction layer.
In a specific embodiment of the invention there is provided a plurality of channels in the friction material layer and. resilient material layer of a depth substantially equal to .the depth of the grooves, which channels extend from the inner periphery to the outer periphery of the friction material layer, with each channel tapering from a given d~mension at the inner periphery to the dimension smaller than the given dimension at the outer periphery, to transfer fluid to ~he grooves along the radial extent of the disc assembly.
The clutch of the invention may be a fluid actuated, fluid cooled, slippable, speed-responsive, starting clutch which is mounted on a shaft and is coaxial with the driven mab/
or ou-tput pulley. A forward-neutral-reverse gear means, hereafter forward-reverse, may be mounted along the shaft and a countershaf~. The starting clutch, when engaged, provides a driving connec~ion between the shaft and the forward-reverse gear means, so that the belt and the pulleys of the CVT continuously rotate in the same direction no matter which direction of drive (forward or reverse) is selected. A control system may be provided for regulating the fluid volume in one fluid circuit and pressure in a second fluid circuit -to thereby effect the sheave gap of the pulleys, and the operation of the slippable s-tarting clutch, and the flange load on the belt.
One way of carrying out the invention is described in détail below with reference to drawings which illustrate only one specific embodiment~ in which:-` FIGURE 1 is a diagrammatic view of a variable pulley transmission system in a drive train at a low drive or i.dle c.ondition;
FIGU~E 2~ is a detailed illustration of the trans-mission assembly along the first two axes of the assembly;
FIGURE 2B is a detailed illustration of -the trans-mission assembly a].ong the last two axes; and FIGURE 3 is an enlarged showing of the slippable starting clutch;
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~ IGURE 4 is a cross-section view of a c3utch disc assembly;
FIGURE 4A is a cross-section view si.milar to that o FIGURE 4, but taken on an enlarged scale to show structural details;
FIGURE 5 is a plan view depicting a s gment o~ an annular clutch plate with an oil-groove pattexn; and FI~URES 6-8 are graphical illustrati~ns useful in understanding the operation.
In the drawings like numbers refer to like elements.
: . .. . . . .
.... .
FIGURE 1 is a diagrammatic drawing of an assembly of a transmission mechanism 10 in a drive train connected to a prime mover 12, noted as an engine. The assembly 10 has four horizonta:L and parallel axes lettered A, B, C and D. The assembly includes a continuousl~ variable pulley trans-mission (CVT) 14, connected between axes A and B, 2Q a slippable starting clutch 16 on axis B, a forwa.rd-reverse gear means 18 on axes B and C, and a final dri.ve assembly 20 along axis D. A ~rans mission control means 22 is shown along axis A.
The power train elements in FIGURE 1 distributed along axis A from the prime mover 12 are a first shaft 24, coaxial with axis A, on which shaft 24 is. A torsional vibration damper 28 is drivingly connected to shaft 24r which damper 28 is affixed to a flywheel 26 connect.ible tc the prime mover 12. Mounted on shaft 24 is an input variable driver pulley assembly 30 which includes a fixed sheave 66 and a movable sheave actuator 32, and the transmission control means 22.
Affixed to and operable with fixed sheave 66 is a sprocket 31. A fluid pump 33, which is illustrated as offset ~rom the axes ~ through D, has a shaft 39 on which shaft 39 there is af~ixed a second sprocket 35 which is drivingly connected by a linking means 37 to sprocket 31. ~luid pump . . 33 is continuously driven by shaft 39 during engine operation to supply fluid at line pressure through conduit means not shown.
Mounted along axis A, between pulley 30 and control means 22~ and driven hy shaft 24 is a lubricating pump 136.
Coaxial with second axis B is a driven shaft 34~ Mounted on the shaf-t 34 is an output variable driven pulley assembly 36 which includes a movable sheave actuator 38, cluster driver gears 40 o~ the forward-reverse gear means 18 and the slippable starting clutch 16, which is fluid-actuated and controlled by control means 22. Input pulley 30 and output pulley 36 are connected by a belt means ~2.
Axis C is coaxial with a countershaft 43 on which are mounted cluster driven gea.rs 44 of the forward-reverse gear means 18. Driven gears 44 are in continuous engagement with drivex gears 40 on shaft 34~ Operative be-tween the forward and reverse drIven gears 44 and splined on countershaft 43 is a synchronizer 46 which is slidably connected to a gear shift rail 47 to selectively engage either the forward or reverse gear of driv~n gears 44. Splined to and driven by shaft 43 is a pinion gear 48. A differential assembly 50 of final drive assembly 20 defines a flange 52 on which is mounted a ring gear 54. Ring gear 54 is continuously engaged with pinion gear 48. Mounted and operative between cluster driver gears 40 and .... ..
: driven gears 44 is a reverse idler gear 41, as known in the prior art.
The final drive assembly 20 is coaxially mounted along axis D and includes a drive axle 56.
Differential assembly 50 is connected to the drive axle 56 in a manner known in the prior axt.
.
Referring now to FIGURE 2A, a vib.ration damper 28 is shown mounted on shaft 24 and connected to flywheel 26 with year teeth 27, and this two element combination of vibration damper and flywheel is protectivel~ covered by a housing 58.
Mounted in housing 58 above the teeth 27 of flywheel 26 is a magnetostrictive device 57 of a type ~nown in the prior art to produce an electronic signal which is communicated to control means 22 by z conductox means 59. This signal is calibratable through control means 22 as a measure of input speed. Housing 58 defines a bore 60 Shaft 24 with a bearing asse~bly 64 mounted thereon extends thxough bore 60 to re~ain bearing 64 therein.
Driver pulley assem~ly 30 is mounted on shaf~ 24 internal to housing 58 and downstream from bearing ~4.
Driver pulley assembly 30 includes a ~ixed sheave 6~ and a movable sheave 68. ~ixed sheave 66 defines an inner sloped face 70 and~ in co- -operation with shaft 24 defines a sleeve 72 with a shoulder 73, a fluid conduit 74 and a passage 76 with ports 78 and 80. Movable sheave 6B defines an inner sloped face 82, an extended ~rm 84, a sleeve 86, fluid passage 88 with ports 90,92, an inner cha~ber face 94, and an inner cha~ber surface ~6 of arm 34. Sleeve 86 and sleeve 72 cooperat~
to deine annular fluid chamber 98, and a ball track 100 wherein bearin~ ball 102 are positioned to thereby ball-spline sleeve 86 about sleeve 7~. An annular piston flange 104 with a wall 105 is formed to define a recess 106, a bore 108 and a brace wall 110~ The bore 108 and wall 110 axe ~5 slidably pressed onto shaft 24 against shoulder 73. Rece.ss 106 with a shoulder 107 can receive sleeve 86 and has wall 110 to bear a thrust load.
~lange 104 with a lip seal 103 sealingly contacts inher chamber surface 96 of arm 84, and surface 96 cooperates with inner chamber face 94 and sleeve 86 to define a fluid volume chamber 114 which co~municates to fluid conduit 74 through ports 78,80,90 and 92, passages 76 and 88 and fluid chamber 98. A flange cap 116 has a wall 118 conforming generally to the shape of piston ~lange 104 without contacting flange 104. Cap 116 is affixed to arm 84 and is movable with movable sheave 68. Wall 118 defines a bore 120 that is slidable along shoulder 107 of recess 106 but does not bear on shoulder 107~
Wall 118 defines a fluid vent hole 119 to allow fluid linkage to evacuate during pulley 30 .
rotation from the gap between piston flange 104 and cap flang~ 116.
An annular bearing assembly 122 is pressed on sleeve 72 against wall 110 and secured in that . position hy a lock nut 124 affixed to shaft 24, both bearing 122 and lock nut 124 are kno~n in the prior art. A housiny 126 defines a bore 128 to receive and retain bearing assembly 122~ Housing 126 is secured by means 127 known in the art to housing 58. A tubular insert 130 is positioned in 1uid conduit 74 and extends through bearing 122 and lock nut 124 and has mounted about this extended portion a ca.p 132 having walls 134 pressed into bore 128 to abut bearing 122 without disturbing loc~ nut 124.
A gerotor pump 136 for lubrication only, such as those manufactured by Nichols Corporation, has a cover 138 defining a recess 140 to receive the tubular insert 130. There is a cross-drilled hole 141 defined by cover 138 that allows communication 37~
from an external source to the conduit 74 through tubular insert 130. The pump 136 .is affixed to housing 126 by means known in the art. Tubular insert 130 is held by locking pins 142,144 secured to sleeve 72 and pump 136, respectively, Belt means 42 connects dri~er pulley assembly 30 with driven pulley assembly 36 which driven pulley 36 is mounted on shaft 34 that is coaxial with axis B. Belt means 42 is known in the prior art.
Pulley assembl~ 36 has a ~i~ed sheave 150 and a movable sheave 152 which is movable in an axial direction along shat 34. Shaft 34 defines a through-hole fluid conduit 154 extending longi-. tudinally through shaft 34. This conduit 15.4 has been reamed at both ends and receives a Eluid source connectible insert 156 communicable to a fluid source at one end, and a lubricating insert - 158,known in the art, and an end-plug 160 at the opposite end. Shaft 34 deEines lubricating passage 162 with ports 164,166 and a second lubricatin~ passage 168 with ports 170,172 which passages and ports communi.cate with lubrica-ting insert 15~. Shaft 34 de:Eines shoulders 171 and 173, a fluid passage 174 with ports 176 and 178 and a second fluid passage 180 with ports 182 and 184, in proximity to clutch 16.
Movable sheave 152 includes an exterior sloped ~ace 186 and an interior wall 187, an extended rim 188 with a contact surface 190, a sleeve 192, and a rib 193 pro~ruding froM wall 187. Sleeve 192 defines a fluid passacJe lg4 and communicating ports 196,198 therewith.. 51eeve lg2 cooperates with shaft 34 to define an annular fluid chamber 200 which communicates be-t~een passages 174 and 194; and, sleeve 192 and shaft 34 also cooperate to de~ine a ball track 202 there-between, in which are positioned bearing balls 204 lD to thereby ball spline movable sheave 152 to shaft 34. A pin ~06 is fitted into shaft 34 extending into track 202 in proximity wi~h passage 174 to serve as a positive stop for bearing balls 204~
An annular piston flange 208 with lip seal 20~, similar to flange 104 of input pulley 30 r is formed about shaft 34. Flange 2Q8 defines a .... ..... .. xecess 210, a surface 211, a bore 212 and a wall ! ` 214. Flange ~08 sealingly contacts extended rim 188 along surface 190. FlancJe 208 defines a shoulder 216, and an orifice 218 of about forty~
five thousandths (0.045~ inch diameter which ori~ice 218 can have a "Wiggle Wire" inserted therein to maintain flow but which is not here shown. Affixed to rim 188 at movable shea~e 152 is a balance flange cap 220 that is formed in a ashion similar to flange cap 116 at driver pulley 30. Flange cap 220 defines a ~ore 222 about surface 211 and travels with movable sheave 152 along surface 211 without contactincJ it~
Movable sheave 152 and piston flange 208 cooperate to define annular ~luid chamber 224 that communicates with fluid conduit 154 through passayes 174,lg4 and chamber 198. A coil bias spring 226 -- 1() is retained in chal~er 224 against rib 193 of sheave 152 and shoulder 216 of flange 208. Spring 226 biases movable sheave 152 in the direction of fixed sheave 150. Flange 208 and flange cap 220 cooperate to define a fluid pressure ~alancing cavity 228 which communicates with chamber 224 through orifice 21~. Piston flange wall 214 is secured against shoulder 171 of shaft 34 by a bearing assembly 230 which is secured in position on shaft 34 by a lock nut 232 affixed on shaft 34.
Housing 58 defines a bore 234 and shoulder 236 to seat and retain bearing 230, and also defines a recess 235 to enclose lock nut 232.
Mounted at the opposite longitudinal end of .~5. .. shaft 34 from bearing 230 is clutch 16. Mounted on shaft 34 between clutch 16 and ixed sheave 150 of pulley assembl.y 36 axe the cluster driver gears 40 of forward-reverse gear means lg. Dri~er gears ~0 include a forward gear 238 which defines a sleeve 240 with lands 242 and 244. Gear 238 is mounted on and rotatable about shaft 34 and is in proximit~ to but separated fxom fixed sheave 150 b~ a support 246 deined by housing 126. Support 246 defines bore 248 in which is seated and retained a bearing assembly 250 mounted on shaft 34 to maintain support 246 concentric about shaft 34. Abu~ting shoulder 173 of shaft 34 is an annular stop ring 252 against which is mounted a bearing assembly 254. Sleeve 240 is mounted about a bearing 25 positioned on shaft 34 and abuts bearing 254.
~ 11 --Shaft 34 defines a fluid entry hole 258 which communicates to the outer diameter of shaft 34.
Insert 158 defines a passage 260 which can pick up and communicate a measured volume of fluid. This insert 158 transports lubricant to bearing 250, 254 from ~earing 256 through passages 162 and 16$, respectively.
Cluster driver gears 40 have a reverse gear 262 affixed to and rotatin~ with land 242 of sleeve 240~ Reverse gear 262 defines a shoulder 264 on whic~ is affi~ed a sprag gear 266 for the parking mode of the transmission assembly 10.
Cluster driver gears 40 can also be a single assembly. Mounted on land 244 of sleeve 240 is a retaining bearing 268 which is held in position by 15 ~
a flange 270 defined by housing 126~ which flange defines a bore 272 to seat beariny 26~ against an annular stop 271 and a spacer 274. Stop 271 is secured to flange 270 by means known in the art.
Clutch assembly 16 is shown in FIG. 3 in an enlarged ~iew and includes a cup-shaped cover plate 300, a pressure or driven plate 302, a reaction p]ate 30~, a clutch disc assembly 306, a Belleville spring 308 and connecting elementsr Clutch 16 is mounted on shaft 34 where cover plate 300 defines a hub 310 and a tapered bore 312. Clutch 16 is fitted onto shaft 34, positioned by a dowel pin 314 and secured at hub 310 by a locknut 316~ which abuts hub 310 and is screwably affixed to shaft 7~
34. Cover plate 300 defines a front face 318~ a perimeter wall.320, a series of connecting-means portals 322 on its fxont face 318, and a plurality of vent holes 324 equispaced ~n perimeter wall 320. Hub 310 defines a conduit 326 and ports 328, 330. Cover plate 300 and pressure plate 302 cooperate to define an annular clutch fluid pressure chamber 332 which communicates with conduit 154 through passage 180 and conduit 326.
Reac~ion plate.304 is affixed to cover plate 300 by a securing means 334 illustrated as a pin or dowel, this reaction plate 304 has a backface 305. Plate 304 can be secured by any means known in the art~ Clutch disc assembly 306 includes a clu~ch disc 336 with large oll grooves for fluid transfer ~not shown ~ere), an annular ring 342 ana a spline member 344. Clutch. disc 336 has surfaces 337 and 339 which have resilient layers 341 and 343 (shown in Figs. 4 and 4A) affixed thereto and
This is a division of copending Canadian Patent Application Serial No~ 400,560, filed April 6, 1982.
Variable pulley transmission assemblies are known in the prior art and are comprlsed of variable sheave pulleys, a connecting belt means and a control means. In automotive applications it has been necessary to utilize hydrodynamic and/or clutch assemblies as starting devices. This same automotive application requires a means or method to effect a change of direction. It has been found that forward-reverse gear mechanisms having planetary gearing and sepaxate clutches cvuld perform such a task. Planetary gearing also provides a means to attain a desirable gear reduction. Alternatively, a change of direction could be accomplished with a reversal of the pulley rotation. This method of directional change, assuming low belt ratio, requires stopping pulley rotation and initiating motion of ~he drive train members in an oppo~
site direction. Further, a change of belt ratio when the pulleys are stopped requires that the belt be slid across the pulley faces causing wear on both the belt and the pulley surfaces, and requires a great deal of force to perform such a belt movement.
A var.iable pulley transmission assembly may be operable between a prime mover and a driven means. The assembly includes, in order, from the prime mover, a vibration damper, input and output movable sheave pulleys connected by a flexible belt~ a belt ratio control arrangement, a wet clutch, a forward-neutral-reverse gear arrangement and connecting elements to a drive means, generally a differen~
tial drive system with rin~ and pinion gear set. This apparatus is adaptable for use with an automobile where the engine is the prime mover and the final drive means is a dif:Eerenti.al-axle-wheel assembly.
mab/Jc ~^
87~
According to the present invention there is pro-vided a fluid cooled clutch including a generally annula.r laminated clutch disc assembly having an inner and an outer periphery which disc assembly includes a central d,isc with opposed surfaces, a resilient material layer af:Eixed to each surface and a friction material layer affi.xed to each resilient layer where each resilient layer is at least as thck as the friction material layer. A pattern of grooves is provided in the friction material layer, which grooves extend completely through the friction material layer and through substantially all of the resilient layer thus pro-viding a path for coolant fluid :Elow in the laminated struc-t.ure which is subst,antia',.ly greater than that of a grooved friction layer.
In a specific embodiment of the invention there is provided a plurality of channels in the friction material layer and. resilient material layer of a depth substantially equal to .the depth of the grooves, which channels extend from the inner periphery to the outer periphery of the friction material layer, with each channel tapering from a given d~mension at the inner periphery to the dimension smaller than the given dimension at the outer periphery, to transfer fluid to ~he grooves along the radial extent of the disc assembly.
The clutch of the invention may be a fluid actuated, fluid cooled, slippable, speed-responsive, starting clutch which is mounted on a shaft and is coaxial with the driven mab/
or ou-tput pulley. A forward-neutral-reverse gear means, hereafter forward-reverse, may be mounted along the shaft and a countershaf~. The starting clutch, when engaged, provides a driving connec~ion between the shaft and the forward-reverse gear means, so that the belt and the pulleys of the CVT continuously rotate in the same direction no matter which direction of drive (forward or reverse) is selected. A control system may be provided for regulating the fluid volume in one fluid circuit and pressure in a second fluid circuit -to thereby effect the sheave gap of the pulleys, and the operation of the slippable s-tarting clutch, and the flange load on the belt.
One way of carrying out the invention is described in détail below with reference to drawings which illustrate only one specific embodiment~ in which:-` FIGURE 1 is a diagrammatic view of a variable pulley transmission system in a drive train at a low drive or i.dle c.ondition;
FIGU~E 2~ is a detailed illustration of the trans-mission assembly along the first two axes of the assembly;
FIGURE 2B is a detailed illustration of -the trans-mission assembly a].ong the last two axes; and FIGURE 3 is an enlarged showing of the slippable starting clutch;
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~ IGURE 4 is a cross-section view of a c3utch disc assembly;
FIGURE 4A is a cross-section view si.milar to that o FIGURE 4, but taken on an enlarged scale to show structural details;
FIGURE 5 is a plan view depicting a s gment o~ an annular clutch plate with an oil-groove pattexn; and FI~URES 6-8 are graphical illustrati~ns useful in understanding the operation.
In the drawings like numbers refer to like elements.
: . .. . . . .
.... .
FIGURE 1 is a diagrammatic drawing of an assembly of a transmission mechanism 10 in a drive train connected to a prime mover 12, noted as an engine. The assembly 10 has four horizonta:L and parallel axes lettered A, B, C and D. The assembly includes a continuousl~ variable pulley trans-mission (CVT) 14, connected between axes A and B, 2Q a slippable starting clutch 16 on axis B, a forwa.rd-reverse gear means 18 on axes B and C, and a final dri.ve assembly 20 along axis D. A ~rans mission control means 22 is shown along axis A.
The power train elements in FIGURE 1 distributed along axis A from the prime mover 12 are a first shaft 24, coaxial with axis A, on which shaft 24 is. A torsional vibration damper 28 is drivingly connected to shaft 24r which damper 28 is affixed to a flywheel 26 connect.ible tc the prime mover 12. Mounted on shaft 24 is an input variable driver pulley assembly 30 which includes a fixed sheave 66 and a movable sheave actuator 32, and the transmission control means 22.
Affixed to and operable with fixed sheave 66 is a sprocket 31. A fluid pump 33, which is illustrated as offset ~rom the axes ~ through D, has a shaft 39 on which shaft 39 there is af~ixed a second sprocket 35 which is drivingly connected by a linking means 37 to sprocket 31. ~luid pump . . 33 is continuously driven by shaft 39 during engine operation to supply fluid at line pressure through conduit means not shown.
Mounted along axis A, between pulley 30 and control means 22~ and driven hy shaft 24 is a lubricating pump 136.
Coaxial with second axis B is a driven shaft 34~ Mounted on the shaf-t 34 is an output variable driven pulley assembly 36 which includes a movable sheave actuator 38, cluster driver gears 40 o~ the forward-reverse gear means 18 and the slippable starting clutch 16, which is fluid-actuated and controlled by control means 22. Input pulley 30 and output pulley 36 are connected by a belt means ~2.
Axis C is coaxial with a countershaft 43 on which are mounted cluster driven gea.rs 44 of the forward-reverse gear means 18. Driven gears 44 are in continuous engagement with drivex gears 40 on shaft 34~ Operative be-tween the forward and reverse drIven gears 44 and splined on countershaft 43 is a synchronizer 46 which is slidably connected to a gear shift rail 47 to selectively engage either the forward or reverse gear of driv~n gears 44. Splined to and driven by shaft 43 is a pinion gear 48. A differential assembly 50 of final drive assembly 20 defines a flange 52 on which is mounted a ring gear 54. Ring gear 54 is continuously engaged with pinion gear 48. Mounted and operative between cluster driver gears 40 and .... ..
: driven gears 44 is a reverse idler gear 41, as known in the prior art.
The final drive assembly 20 is coaxially mounted along axis D and includes a drive axle 56.
Differential assembly 50 is connected to the drive axle 56 in a manner known in the prior axt.
.
Referring now to FIGURE 2A, a vib.ration damper 28 is shown mounted on shaft 24 and connected to flywheel 26 with year teeth 27, and this two element combination of vibration damper and flywheel is protectivel~ covered by a housing 58.
Mounted in housing 58 above the teeth 27 of flywheel 26 is a magnetostrictive device 57 of a type ~nown in the prior art to produce an electronic signal which is communicated to control means 22 by z conductox means 59. This signal is calibratable through control means 22 as a measure of input speed. Housing 58 defines a bore 60 Shaft 24 with a bearing asse~bly 64 mounted thereon extends thxough bore 60 to re~ain bearing 64 therein.
Driver pulley assem~ly 30 is mounted on shaf~ 24 internal to housing 58 and downstream from bearing ~4.
Driver pulley assembly 30 includes a ~ixed sheave 6~ and a movable sheave 68. ~ixed sheave 66 defines an inner sloped face 70 and~ in co- -operation with shaft 24 defines a sleeve 72 with a shoulder 73, a fluid conduit 74 and a passage 76 with ports 78 and 80. Movable sheave 6B defines an inner sloped face 82, an extended ~rm 84, a sleeve 86, fluid passage 88 with ports 90,92, an inner cha~ber face 94, and an inner cha~ber surface ~6 of arm 34. Sleeve 86 and sleeve 72 cooperat~
to deine annular fluid chamber 98, and a ball track 100 wherein bearin~ ball 102 are positioned to thereby ball-spline sleeve 86 about sleeve 7~. An annular piston flange 104 with a wall 105 is formed to define a recess 106, a bore 108 and a brace wall 110~ The bore 108 and wall 110 axe ~5 slidably pressed onto shaft 24 against shoulder 73. Rece.ss 106 with a shoulder 107 can receive sleeve 86 and has wall 110 to bear a thrust load.
~lange 104 with a lip seal 103 sealingly contacts inher chamber surface 96 of arm 84, and surface 96 cooperates with inner chamber face 94 and sleeve 86 to define a fluid volume chamber 114 which co~municates to fluid conduit 74 through ports 78,80,90 and 92, passages 76 and 88 and fluid chamber 98. A flange cap 116 has a wall 118 conforming generally to the shape of piston ~lange 104 without contacting flange 104. Cap 116 is affixed to arm 84 and is movable with movable sheave 68. Wall 118 defines a bore 120 that is slidable along shoulder 107 of recess 106 but does not bear on shoulder 107~
Wall 118 defines a fluid vent hole 119 to allow fluid linkage to evacuate during pulley 30 .
rotation from the gap between piston flange 104 and cap flang~ 116.
An annular bearing assembly 122 is pressed on sleeve 72 against wall 110 and secured in that . position hy a lock nut 124 affixed to shaft 24, both bearing 122 and lock nut 124 are kno~n in the prior art. A housiny 126 defines a bore 128 to receive and retain bearing assembly 122~ Housing 126 is secured by means 127 known in the art to housing 58. A tubular insert 130 is positioned in 1uid conduit 74 and extends through bearing 122 and lock nut 124 and has mounted about this extended portion a ca.p 132 having walls 134 pressed into bore 128 to abut bearing 122 without disturbing loc~ nut 124.
A gerotor pump 136 for lubrication only, such as those manufactured by Nichols Corporation, has a cover 138 defining a recess 140 to receive the tubular insert 130. There is a cross-drilled hole 141 defined by cover 138 that allows communication 37~
from an external source to the conduit 74 through tubular insert 130. The pump 136 .is affixed to housing 126 by means known in the art. Tubular insert 130 is held by locking pins 142,144 secured to sleeve 72 and pump 136, respectively, Belt means 42 connects dri~er pulley assembly 30 with driven pulley assembly 36 which driven pulley 36 is mounted on shaft 34 that is coaxial with axis B. Belt means 42 is known in the prior art.
Pulley assembl~ 36 has a ~i~ed sheave 150 and a movable sheave 152 which is movable in an axial direction along shat 34. Shaft 34 defines a through-hole fluid conduit 154 extending longi-. tudinally through shaft 34. This conduit 15.4 has been reamed at both ends and receives a Eluid source connectible insert 156 communicable to a fluid source at one end, and a lubricating insert - 158,known in the art, and an end-plug 160 at the opposite end. Shaft 34 deEines lubricating passage 162 with ports 164,166 and a second lubricatin~ passage 168 with ports 170,172 which passages and ports communi.cate with lubrica-ting insert 15~. Shaft 34 de:Eines shoulders 171 and 173, a fluid passage 174 with ports 176 and 178 and a second fluid passage 180 with ports 182 and 184, in proximity to clutch 16.
Movable sheave 152 includes an exterior sloped ~ace 186 and an interior wall 187, an extended rim 188 with a contact surface 190, a sleeve 192, and a rib 193 pro~ruding froM wall 187. Sleeve 192 defines a fluid passacJe lg4 and communicating ports 196,198 therewith.. 51eeve lg2 cooperates with shaft 34 to define an annular fluid chamber 200 which communicates be-t~een passages 174 and 194; and, sleeve 192 and shaft 34 also cooperate to de~ine a ball track 202 there-between, in which are positioned bearing balls 204 lD to thereby ball spline movable sheave 152 to shaft 34. A pin ~06 is fitted into shaft 34 extending into track 202 in proximity wi~h passage 174 to serve as a positive stop for bearing balls 204~
An annular piston flange 208 with lip seal 20~, similar to flange 104 of input pulley 30 r is formed about shaft 34. Flange 2Q8 defines a .... ..... .. xecess 210, a surface 211, a bore 212 and a wall ! ` 214. Flange ~08 sealingly contacts extended rim 188 along surface 190. FlancJe 208 defines a shoulder 216, and an orifice 218 of about forty~
five thousandths (0.045~ inch diameter which ori~ice 218 can have a "Wiggle Wire" inserted therein to maintain flow but which is not here shown. Affixed to rim 188 at movable shea~e 152 is a balance flange cap 220 that is formed in a ashion similar to flange cap 116 at driver pulley 30. Flange cap 220 defines a ~ore 222 about surface 211 and travels with movable sheave 152 along surface 211 without contactincJ it~
Movable sheave 152 and piston flange 208 cooperate to define annular ~luid chamber 224 that communicates with fluid conduit 154 through passayes 174,lg4 and chamber 198. A coil bias spring 226 -- 1() is retained in chal~er 224 against rib 193 of sheave 152 and shoulder 216 of flange 208. Spring 226 biases movable sheave 152 in the direction of fixed sheave 150. Flange 208 and flange cap 220 cooperate to define a fluid pressure ~alancing cavity 228 which communicates with chamber 224 through orifice 21~. Piston flange wall 214 is secured against shoulder 171 of shaft 34 by a bearing assembly 230 which is secured in position on shaft 34 by a lock nut 232 affixed on shaft 34.
Housing 58 defines a bore 234 and shoulder 236 to seat and retain bearing 230, and also defines a recess 235 to enclose lock nut 232.
Mounted at the opposite longitudinal end of .~5. .. shaft 34 from bearing 230 is clutch 16. Mounted on shaft 34 between clutch 16 and ixed sheave 150 of pulley assembl.y 36 axe the cluster driver gears 40 of forward-reverse gear means lg. Dri~er gears ~0 include a forward gear 238 which defines a sleeve 240 with lands 242 and 244. Gear 238 is mounted on and rotatable about shaft 34 and is in proximit~ to but separated fxom fixed sheave 150 b~ a support 246 deined by housing 126. Support 246 defines bore 248 in which is seated and retained a bearing assembly 250 mounted on shaft 34 to maintain support 246 concentric about shaft 34. Abu~ting shoulder 173 of shaft 34 is an annular stop ring 252 against which is mounted a bearing assembly 254. Sleeve 240 is mounted about a bearing 25 positioned on shaft 34 and abuts bearing 254.
~ 11 --Shaft 34 defines a fluid entry hole 258 which communicates to the outer diameter of shaft 34.
Insert 158 defines a passage 260 which can pick up and communicate a measured volume of fluid. This insert 158 transports lubricant to bearing 250, 254 from ~earing 256 through passages 162 and 16$, respectively.
Cluster driver gears 40 have a reverse gear 262 affixed to and rotatin~ with land 242 of sleeve 240~ Reverse gear 262 defines a shoulder 264 on whic~ is affi~ed a sprag gear 266 for the parking mode of the transmission assembly 10.
Cluster driver gears 40 can also be a single assembly. Mounted on land 244 of sleeve 240 is a retaining bearing 268 which is held in position by 15 ~
a flange 270 defined by housing 126~ which flange defines a bore 272 to seat beariny 26~ against an annular stop 271 and a spacer 274. Stop 271 is secured to flange 270 by means known in the art.
Clutch assembly 16 is shown in FIG. 3 in an enlarged ~iew and includes a cup-shaped cover plate 300, a pressure or driven plate 302, a reaction p]ate 30~, a clutch disc assembly 306, a Belleville spring 308 and connecting elementsr Clutch 16 is mounted on shaft 34 where cover plate 300 defines a hub 310 and a tapered bore 312. Clutch 16 is fitted onto shaft 34, positioned by a dowel pin 314 and secured at hub 310 by a locknut 316~ which abuts hub 310 and is screwably affixed to shaft 7~
34. Cover plate 300 defines a front face 318~ a perimeter wall.320, a series of connecting-means portals 322 on its fxont face 318, and a plurality of vent holes 324 equispaced ~n perimeter wall 320. Hub 310 defines a conduit 326 and ports 328, 330. Cover plate 300 and pressure plate 302 cooperate to define an annular clutch fluid pressure chamber 332 which communicates with conduit 154 through passage 180 and conduit 326.
Reac~ion plate.304 is affixed to cover plate 300 by a securing means 334 illustrated as a pin or dowel, this reaction plate 304 has a backface 305. Plate 304 can be secured by any means known in the art~ Clutch disc assembly 306 includes a clu~ch disc 336 with large oll grooves for fluid transfer ~not shown ~ere), an annular ring 342 ana a spline member 344. Clutch. disc 336 has surfaces 337 and 339 which have resilient layers 341 and 343 (shown in Figs. 4 and 4A) affixed thereto and
2~ friction facings 338 and 340 respectively mounted thereon. This composite arrangement is p~sitioned between and engageable by pressure plate 302 and reaction plate 304. Disc 336 is drivin~ly affixed to the outer perimeter of annular ring 342 and -this combination is secured to the spline member 344 at the inner diameter o~ annular ring 342, which spline member 344 is splined to sleeve 240 of forward gear 233.
Clutch 16 is fluid actuated and, according to the present invention, is cooled. Coolant is provided through a fluid conduit 346 .
7~
connected to a fluid source (not shown in FIGURE
Clutch 16 is fluid actuated and, according to the present invention, is cooled. Coolant is provided through a fluid conduit 346 .
7~
connected to a fluid source (not shown in FIGURE
3). Plate 304, annular ring 3~2 and plate 271 define an open cavity 348.
~, A thin metal annular sheet 347 affixed to p~ate 271 is in a plane parallel to face 305 of driven plate 304 of clutch 16. ~lange 270 and metal plate 347 define a wide passage 349 which communicates with conduit 34~. Plate 271 defines a large port 276 which communicates between passage 349 and cavity 3~8. ~eaction plate 304 defines a shoulder 350 to retain the cooling fluid in clutch cavity 348~during rotational motion o~ the clutch.
Clutch disc assembly 306 and pressure plate 302 coop~rate to define an irregularly shaped annular - 15~ cavity 352 in clutch 16 which cavity 35~ communicates with vent holës 324 of cover plate 300. Annular ring 342 defines a series of communicating po.rts 354 to.communicate coolant fluld from cavity 348 to cavit.y 352 and thereafter past both faces of clutch plate-336 and thus to provide coolant fluid emission through vent holes 3~4 during rotation of the clutch 16.
Pressure plate 302 is connected to zero rate (as explained in U. S. Patent No. 3,951,393~
Bellevill~ spring 30B by connecting means 356 through portals 322, and plate 302 is biased by spring 30B to a disengaged condition as illustrated in ~IG. 3. Pressure.plate 302 is fluid actuated by fluid pressure in chamber 332 ade~ua-te to overcome the force of Bellcville spring 308 and to thrust pressure plate 302 in an axial di.rection - into contact with clutch disc assembly 306 and, therethrough, into driving communication with S reaction plate 304 through friction faces 338, 340 r Mounted in proximity to vent holes 324 is a magnetostrictive device 358, although any similar transducer signal generator would do, that monitors a magnet.ic field effec-t change inauced by the change in plate mass as each vent hole 324 passes - it. This device 358 is known in the prior art and produces a signal that can be calibrated through control means 22 to indicate pulley 36 output Speed, . .
Referring to ~IG. 2B driven gear means 44 of forward-reverse gear means 18 of FIG~ 1 includes a forward gear 384 and a reverse gear 390, with bearing means on countershaft 43 which is coaxial with axis C. ~lange 270 defines a bore 362 -for seating a bearing assembly 364 which is secured in p~sition by a snap .ring 366 set in an undercut in flange 270. A thrust plate 368 is mounted on countershaft 43 on the opposite side of bearing assembly 364 from snap ring 36~ and these elements are .reta.ined on the end of sha:Et 43 a~ainst driven gear5 D~ ~ .
Countershaft 43 defines a thrust shoulder 370, land 372, spline 374 and land 376 each shown with a smaller cross-section on shaft 43 than the . - \~
previously mentioned cross~section. A toothed ring 375 is splined to shaft 43 at spline 374 and synchronizer 46 is slidably mounte~ thereon.
Shaft 43 also defines a blind-drilled lubricating condui-t 378 along its longitudinal axis an~, fluid lubricating passages 380 and 382 which communicate ~etween conduit 378 and lands 372 and 376, res-pectively, at the surface of shaft 43. Lubricating fluid can be communicated to conduit 378 through a conduit means 379 mounted in the en~ of conduit 378 and connectible to lubricating pump 136, shown in ~IGo 2A~ Journalled on land 372 of shaft 43 and abuttin~ shoulder 370 is forward gear 384 of driven gears 44. This forward gear is freely rotatable about countershaft 43 and is in continuous engagement with driver forward gear 238 on shaft -- 34. Pressed on land 376 of shaft 43 is a bearing assembly 388 on which is mounted r~verse gear 390 o driven gear means 44. This gear 390 is freely rotatable about countersha-Et 43 and continuously engaged with reverse idler gear 41 of FIG. 1 of gear means 40 as known in the art. Slidably mounted on toothed ring 375 is synchronizer 46 that defines an annular groove and which synchronizer 25 46 is slidably engageable with either forward gear 384 or reverse gear 390. Synchronizer 46 also has a neutral position between these forward and reverse gears 384, 390 and is slidable by a gear seleetion fork 392 positioned in ~roove 394 defined by synchronizer 46. Synchronizer 46, at engagement with either forward 384 or reverse 390 gears -transfers power thro~lgh countershaft 43 to ring gear 54 mounted on the differential assembly 50 Qf the final drive assembly 20. Power is transferred to an axle or wheel arrangement as known in ~he prior ark and as illustrated in FIG. 1.
FIGS. 4 and 4A illustrate a part of the laminated clutch disc assem~ly 306 where the clutch disc 336 is a single narrow annular plate.
Disc 336 has opposed surfaces 337 and 339. Affixed to each of these surfaces 337,339 is a resilient material îayer, 341 and 343, respectively, such as Armstrong Cork Company~ 5 NC-711 material, which is a cork and neoprene composition. Mounted on ana affixed to each of these energy-absorbing material layers 341 and 343 is a friction facing material - - layer 338 and 340, respectively. This laminated clutch structure is generally very narrow in width, that is, on the order of 0.180 to 0 192 inch noted as dimension "x". Each of these resilien~
layers 341,343 is at least as thick as the thickness of the friction layexs 338 and 340, and preferably twice as thick as the friction layers.
FIG~ 5 illustrates a segment of an engaginy face of the friction facing material 33B or 340 on the clutch disc assembly. As shown, a pattern of oil grooves 345 is deEine~ on the friction facin~
layers. The result appears as a waffle pattern, that }s, equal surface areas, genPrally rectangular islands 353 of at least one-twenty fifth square inch in surface area. Clutch disc assembly 306 laminated structure has an inner periphery 355 and 7~
an outer periphexy 357 ana the friction material layers are disposed between these peripheries Islands 353 are clustered in groups which appear as arcuate seyments~ These arcuate segements define tapered channels 351 therebetween.
Each channel 351 has a given dimension at inner periphery 355, and the channel tapers, becoming gradually narrower as it extenas to outer periphery 357. At the outer periphery~ the channel width is reduced to a very small dirnension, of the order of one to three hundredths of an inch in the illustra~ed e~bodiment~ F.l.uid communication ports 354 are proviaed in clutch disc 306 providing a passage for cooling oil to inner periphery 355 of the friction material layer. From this location .. the cooling oil enters the throats of channels 351, which in turn communicate with grooves 345 of friction surface layers 338 and 340. Channels 351 appear as discontinuities in the otherwise continuous cross-hatched or waffle pattern ~n these friction surfaces.
In accordance with an important aspect of the invention, the depth of grooves 345 is at least twice the thicXness of friction layer 338 or 340.
This added depth provides a much greater volumetric flow ~or cooling fluid than is otherwise possible, with a consequent increase in cooling effectiveness.
To provide the requisite volumetric flow, grooves 345 extend into the resilient material layer~ If the resilient material layer is as thick as the friction material layer, the grooves extend -~hrough substantially all of the resilien~ layer.
In a preferred embodiment, the resilient layers are substantially twice as thick as each of the friction material layers. In this case the grooves 345 extend completely through the fric-tion material layer (338 or 340~ and through substantially one-half the resilient layer (341 or 343~. The ooolant fluîd ~low can be waste fluid from the high pressure control line diverted through the clutch coolant conduit 346 before its return to a sump., This large volume of waste oil is transferred through the extra deep grooves of the clutch friction facing and resilient layers, to provide much more effective cooling than is accomplished with conventional clutch structures. The coolant is transferred to conduit 346 through a large, , about three-quarters of an inch deepl ditch at ' less than one PSI pressure.
Transmission mechanism 10 is responsive to a ,control system 22 signal. The mechanism 10 provides a slippable starting clutch 16 that is fluid cooled and fluid pxessure actuated. The variable pulley system 14 of mechanism 10 is likewise fluid operated. At prime mover 12 start-up~ the con-tinuously variable pulley transmission (CVT~ 14 is as shown in the upper halves of pulley5 30 and 36 in FIG. 2, that is, where the belt 42 is at its bottom travel or low belt ratio in the driver pulley assembly 14 and the engine flywheel 26 is affixed to prime mover 12 as in FIG. 1. ~otational velocity is transmitted to driver pulley assembly 7~
30 by shaft 24 and thereafter throuyh belt 42 to - driven pulley assembly 36. Driven pulley assembly 36 continuously drives shaft 34, which is affixed to fixed pulley sheave 150, and to clutch cover plate 300 at the hub 310 with locknut 3167 Clutch 16 engagement proviaes a driving connection to synchronized forward-reverse di-rectional gear means 18 from pulley system 14.
The use of gear means 18 obviates the necessity to change belt direc~ion~to provide a change of direction to the final drive assembly 20.
Driving power from clutch 16 is provided to the driver gears 40 of forward-reverse gear means 18 through sleeve 240 which is mounted on and rotatable about shaft 34. Forward gear 238 is a~fixed to sleeve 240 and is con-ti.nuously engaged to forward gear 384 of the driven gears 44 of gear means 18, which driven gears 44 are mounted on and freely rotatable about countersha~t 43.
Drivingly mounted on sleeve 240 is a reverse gear 26~ of driver gears 40 of gear means 1~ which, in conjunction with an idler gear 41, continuously engages reverse gear 3~0 of driven gears 44 ~f ~ear means 18 which is bearing-mounted on counter-shaft 43 and forms a revexse gear arrangementknown in the prior art. Mounted on land 264 of reverse gear 262 on shaft 34 is a parking sprag 266 which is engageable at the stoppea or park position, and such gear engagement is well known in the pxior art. Synchronizex 46 is splined on ring 375 which is rigidly splined on countexshaft 43. The synchronizer is operable by shifting fork 392. The synchronizer 46 is positioned between and slidabl~ engageable with either the forward or reverse gears of driven gears 44. At synchronizer 46 engagement, as drive is being provided through engaged clutch 16, power is transmitted to the final drive assembly 20 in either a forward or reverse direction.
At transmission idle the prime mover 12 is driving in.put pulley 30 through a flywheel 26, vibration damper 28, and drive shaft 24. As sho~n in FIG. 2A, upper halves of pulleys 30 and 36 are shown în low belt ra~io (iOe., driver pulley 30 at lS maximum gap opening and belt 42 at closes~ ra~ius to drive shaft 24). Pulley~30 is utilized ~o control the belt position or ratio and not belt tension or output torque of the drive train. The change of width between fixed sheave 66 and movable sheave 68 of pulley 30 provides the change in belt ratio in response to $he transmission control means 22. This ratio control in the case shown in FIG. 2A, is provided for b~ an introduction o~ a fluid to sealed chamber 114, such as from a fluid ~5 supply means communicating with fluid passage 74 through insert 130 therein to passage 76 t chamber 98 and passage 88. A change in fluid volume into chamber 114 will proportionally move sheave 68 to reduce the sheave gap. As belt 42 travels from the inner radius of pulley 30 to the outer radius, ~9~
the transmission belt ratio changes from low to high with a range of about 5.4 to 1.
Purnp 136 is a*fixed to shaft 24 and only provides lubricant to the various wearing parts of the transmission at a rela-tively low pressure, that is in tlle range of a~out 20 psi. Con-trol fluid for chamber 114 passes through a counter-drilled hole 141 of pump 136 in the face of cover 138 and thus to *luid passage 74.
Output ariven pulley 36 is also fluid operative, however, as driver pulley 30 sheave gap decreases the driven pulley 36 sheave ~ap increases, and in FIG. 2A this implies that ~elt 42 would proceed from the outer radius to the inner radius of pulle~ 36. The sheave gap of the driven pu7ley 36 is determined by the position of movable sheave 68 of driver pulley 30 through belt 42. Control 1uid, at a line pressure controlled by control means 22, is freely communicated to control fluid cavity 224 o~ driven pulley 36 throush inser-t 1560 through hole conduit 154, passage 174, cha~ber 200 and passage 1~4. The piston area of movable sheave 152 within cavi~y 224 is noticeably smaller than its counterpart of driver pulley 30~ Control fluid in cavity 224 is bled to *luid cavi-ty 228 through orifi.ce 218 in piston flange 208. Fluid is transferred to cavity 228 to balance the centrifugal component of the total pressure on either side of flange 208 thereby avoiding a centri*ugal thrust on sheav~ 152. The movable sheave :l52 has a bias spring 226 acting on it and biasing the sheave to minimize the sheave gap width The through-hole conduit 154 provides a transfer means for ~ontrol fluid for slipp~ble starting clutch 16, which is engaged through fluid pressure in cham~er 332, see FIG. 3. The force of the Belleville spring 308 of clutch 16 ten~s to maintain pressure plate 302 in the non-contacting or open position. When the fluid pressure in cavit.~ 332 is sufficient to overcome the Bellevill~
spring 3~8 i-orce, pressure plate 302 is pressed - into contact with friction ~acing 340 to thereaftex engage driven plate 304. Coolant fluid is supplied through control means 22 and conduit 346 to cooling fluid cavity chamber 348 of clutch 16~ At clutch engagement pressure plate 302 contacts friction Eacin~ 340 to dri~ingly engage driven plate 304.
Driving power is thus provided to hollow sleeve 240 of driver gears 40 through disc 336, annular ring 342 and spline member 344~ Therea~ter, rotational motion is communicated to forward gear 233 and reverse gear 262, which gears are rigidly connected, to each other, ana through which shaft 34 extends~ and about which shaft 34 forward~
reverse gears 238, 262 are ~reely ro~atable.
Forward or reverse drive direction, or neutral, if desired, is selectable by operation oE synchronizer 46. The synchronizer 46 position is slidably operable by the fork 392 and rail 47, as known in 3Q the prior art. The forward, reverse gears 334 J
390 on countershaft 43 are in constant engagement with matiny forward year 238, on shaft 340 or idler 41, respectively~ At synchronizer 46 en-gagement rotational motion is transferred to th~
final drive assembly 20, which assembly includes elements such as a differential 50 and drive axle 56 as known in the prior art~
In the operation of this transmission mechanism the pulley system 14 is in constant unidirectional rotary motion whenever prime mover 12 is operating.
All power to the final drive assembly 20 must be communicated from the pulley system 14 through the slippable starting clutch 16, and forward-reverse gear means 18~ In this arrangementJ the con-trol means 22 controls fluid line pressure in passage 154 and fluid volume in chamber 114 based on engine (input~ speed, output speed, throttle (not shown) position and year shift lever 47 position~
The volume of oil in pulley 30 is controlled by means 22 in response to each throttle position to maintain a constant input RPM. For example, during acceleration at one-quarter wide open throttle, means 22 may be progra~ned to maintain a fixed input ~PM, such as 1500 RPM input speed while the belt ratio is be.ing varied Erom low to high ratio. Conversely, at that throttle opening during a condition of vehicle speed reduction~
such as from climbing a grade, the input RPM will be maintained by changing the belt ratio toward low through a discharge of fluid from pulley 30.
In the starting mode the control means 22 increases the fluid pressure in clutch 16 as a function of the engine input RPM ~for eY~ample, as the square o the illpUt RPM). Therefore, at a given throttle opening, a constant torque and a constant RPM will be maint~ined at clutch pressure plate 302 and the ve~icle will accelerate from rest at a constant rate~ With the increase in vehicle speed t the RPM
of the driven plate increases a~ a fixea (geared) ratio until it reaches the cons~ant RPM of the clutch pressure plate 302, which aefines the ena-point of clutch slip, or the end of the startingmode.
FIG. 6 shows the increase of clutch driven plate speed as a ~unction of vehicle speed ~n a curve 600. As shown there is a corresponding - 15 vehicle speed (in miles per hour or MPH) for each particular dri~en plate speed ~in revolutions per m;nute or RPM). Curve 600 indicates that vehicle speed and clutch pressure plate speed intersect at a point 602. At that point, the starting clutch is at the end of its slipo From the origin until the end of clutch slip, th~ angular speed o~ clutch reaction plate 304 rises proportionally with vehicle speed, and this rise is dependent upon gear ratio, not belt ra-tio. The pr~ssure 25 or driver plate 302 is rotating at a constant speed (at a given throttle opening~.
Also in the s~arting mode at the first momPnt ~efore a vehicle has attaine~ a measurable velocity the input torque when plotted as a predetermlned function of engine speed can be/ for example, a paraholic curve similar to a hydrokinetic device or a centrifugal clutch~ In ~IG. 7 t curve G04 is a parabolic function showing the variatlon of input clutch torque (in ft.-lbs.~ or net pressure (in psi) on clutch pressure plate as a function o~
engine speed, where the abcissa commences at a value connoting engine idle speed, rather than zero RPM. ~lso the pressure at engine idle speed is controlled to cancel the opposing force o~ Belleville spring 308 so the net pressure on the clu-tch pressure plate is zero at normal engine idle speedg and consequently creep is avoided~ Creep is defined as the power transfer through the drive train at stall speed sufficient to overcome rolling resistance~
A second general ~unction 606 with a maximum - value at point 608 is also shown. This second function 606 represents the net engine torque at wide open throttle as a function of engine spee~.
The intersection of curves 604 and 606, at poin~
610, indicates the stall point. This is not a different stall point than that previously noted, but explains the same point utilizing dif-Eerent parameters. The continuation of the parabolic curve 604 abo~e the stall point 610 represents the reserve pressure at the clutch pressure plate.
The input tor~ue beyond point 610 is limited to the maximum engine torque 60~ The control means 22 accordingly limits the rise in pre~sure to a predetermined value 612 to provide a controlled reserve pressure slightly above the wide open throttle tQrque requirement. Correspondingly r a suitable reserve pressure is provided at other torques down to about 25~ of the torque at wide open throttle. This mlnimum value also correspon~s to the max;mum engine ~raking torque. This provides a means to protect pulley system 14 from incurring slip and reduces ~elt 42 loading that would o-therwise tend to fatigu2 the bel-t.
Clutch 16 is a liquid cooled (wet~ starting clutch.which is slippable in the starting mode as torque is provided to the final drive assembly 20 At clutch 16 dlsengagement the fIuid pressure in chamber 332 is removed and the Belleville spring .. ... ;.. ... .
. ~ 308 acts to retract pressure plate 302 to the disengaged position. This reaction is almost instantaneous, that is, on the order o~ one-tenth (0.1) second.
Curve 614 in FIG. 8 is generally similar -to curve 604 in FIG. 7. Curve 614 will be used, in conjunction with representative values rounded of~
to whole numbers for ease of cvmprehension, and these values do not limit the present invent;on.
Curve 614 shows clutch torque p:Lotted as a function o engine speed. In this example, wide open th.rottle in the starting mode is indicated at stall point 616, correspond~ng to 2100 RPM and a clutch torque load of 140 ~t.-lbs. At this 2100 RPM engine speed, if the bel-t is at a 1:2 under-drivP ratio/ at point 616, at this low belt ratio 8~
there is effectively a 140 ft.-lbs. clutch torque.
However, the clutch torque for a 2:1 overdrive ratio, at this same throttle opening, is effectively 35 ft.-lbs. In this example, the engine RPM for the 35 ft.-l~s. clutch torque on the curve is denoted at point 618, corresponding to 1300 RPM, which becomes the new stall point, and at this high belt rato of 2:1, point 618 also represents the lugging limit.
~ In other words lugging below this engine speed is inherently avoided along with the harshness or torsional disturbance associated with lug~ing at very low speed particularly so with ~our cycle engines~ At vehicle speeds below the lugging ~5 - limit, the clutch begins to slip and a torsional disturbance associated with such lower speeds will not be transmitted through the clutch. Relow the lugging limit engine speedl the control means 22 will again downshift and the engine speed will increase even at a lower vehicle speed tc thereby remain above the lugging limit.
In a conventional CVT with a startin~ device on the input side o~ the belt stall point is the same in both high and low belt ratios at any given throttle opening, and it is then necessary to add a lock-up device in order to operate the engine in the more efficient speed range below the stall point and this device still does not provide an inherent lugginy limit.
The use of a slippable starting clutch and a forward-reverse gear mechanism provides a compact 7~
arrangement o~ elements to provide power transferO This mechanism is in lieu of multiple clutch packs or heavier, more complex planetary ~ear assemblies as shown in U.S.
Patent 4,342 r 238, issued August 3, 1982.
Clutch 16 is cooled through cooling paths cut in f~iction facings 338,340 and resilient layers 341,343, respectively. This cooling is provided by fluid passing through the waffle pattern on the friction facing. The coolant fluid is waste fluid, such as oil~ diverted from a low pressure return line o~ control means 22. This fluid does not, therefore, require added pump capacity for the high pressure fluid line and as fluid conduit 349 is a relatively large passage, added coolant through the clutch avoids excess back pressure on the control means 22 These large passages permit large volume flows at low pressures thereby obviating high fluid pressures from a pump source and providin~ greater cooling capacity than is presently known.
In the illustrated embodiment, driven pulley 36 is in a centrifugally balanced condition, that is the centrifugal component of the fluid force on either side of flange 208 is virtually equal, thereby avoiding an im-balance Erom a centrifugal pressure effect within chamber 2240 The clamping force and, therefore, the tension on belt 42 is provided by khe fluid pressue ~n chamber 224 and bias spr~n~ 150. This clamping force varies with the ~luid pressure controlled only to -that pressure required to limit belt creep at a ~iven torquer In the prior art it has been the practice to maintain a lar~e fixed force on the belt 42, regardless of torque input, to thereby ~void belt slip. The prior art overloaded belt, at part en~ine load, increases belt fatigue and ~riction losses, and is an added load on the engine or 1uid pressure supply system.
mab/
The attainment of output speed and final gear ratio is through the single paper plate clutch where clutch 16, clutch disc 336 and pressure plate 302 are running at the same speed, having arrived at a locked up state without a jump or lurch, and without a speed differential at lock-up. Those goals were attained through the use of a forward-reverse gear mechanism in con.junction wi-th a wet clutch while also reducing the number of parts and total weight of the assembly~ Such advantages are very important to the automotive industry wherein government regulations require improved fuel efficiency; such an improvement in efficiency is directly proportional to weight losses. In addition, th.s is the most compact automatic transmission currently available. The economies of reducing the number of parts in any assembly while accom-plishing the same task provides cost savings of both material and assembly laborv . , ~ ... .
The above~described transmission mechanism is also described and is claimed in above-identified parent appli-cation Serial No. 400,560 The operability of this transmission clearly obviates the use of multiple clutch packs and planetary gear sets. Furt.her the clutch as disclosed, gives an almost instantaneous disengaging response just by releasing the fluid pressure from the clutch. The use of the combination of elements disclosed gives the user improved cost econo-mies, faster :response time, bettex control, less wear of CVT elements and better fuel economy without a creep con-dition and without a garage shift thump and also proyides better u-tili~ation of fluid with reduced output requirements on the fluid pump~
mab/J
~, A thin metal annular sheet 347 affixed to p~ate 271 is in a plane parallel to face 305 of driven plate 304 of clutch 16. ~lange 270 and metal plate 347 define a wide passage 349 which communicates with conduit 34~. Plate 271 defines a large port 276 which communicates between passage 349 and cavity 3~8. ~eaction plate 304 defines a shoulder 350 to retain the cooling fluid in clutch cavity 348~during rotational motion o~ the clutch.
Clutch disc assembly 306 and pressure plate 302 coop~rate to define an irregularly shaped annular - 15~ cavity 352 in clutch 16 which cavity 35~ communicates with vent holës 324 of cover plate 300. Annular ring 342 defines a series of communicating po.rts 354 to.communicate coolant fluld from cavity 348 to cavit.y 352 and thereafter past both faces of clutch plate-336 and thus to provide coolant fluid emission through vent holes 3~4 during rotation of the clutch 16.
Pressure plate 302 is connected to zero rate (as explained in U. S. Patent No. 3,951,393~
Bellevill~ spring 30B by connecting means 356 through portals 322, and plate 302 is biased by spring 30B to a disengaged condition as illustrated in ~IG. 3. Pressure.plate 302 is fluid actuated by fluid pressure in chamber 332 ade~ua-te to overcome the force of Bellcville spring 308 and to thrust pressure plate 302 in an axial di.rection - into contact with clutch disc assembly 306 and, therethrough, into driving communication with S reaction plate 304 through friction faces 338, 340 r Mounted in proximity to vent holes 324 is a magnetostrictive device 358, although any similar transducer signal generator would do, that monitors a magnet.ic field effec-t change inauced by the change in plate mass as each vent hole 324 passes - it. This device 358 is known in the prior art and produces a signal that can be calibrated through control means 22 to indicate pulley 36 output Speed, . .
Referring to ~IG. 2B driven gear means 44 of forward-reverse gear means 18 of FIG~ 1 includes a forward gear 384 and a reverse gear 390, with bearing means on countershaft 43 which is coaxial with axis C. ~lange 270 defines a bore 362 -for seating a bearing assembly 364 which is secured in p~sition by a snap .ring 366 set in an undercut in flange 270. A thrust plate 368 is mounted on countershaft 43 on the opposite side of bearing assembly 364 from snap ring 36~ and these elements are .reta.ined on the end of sha:Et 43 a~ainst driven gear5 D~ ~ .
Countershaft 43 defines a thrust shoulder 370, land 372, spline 374 and land 376 each shown with a smaller cross-section on shaft 43 than the . - \~
previously mentioned cross~section. A toothed ring 375 is splined to shaft 43 at spline 374 and synchronizer 46 is slidably mounte~ thereon.
Shaft 43 also defines a blind-drilled lubricating condui-t 378 along its longitudinal axis an~, fluid lubricating passages 380 and 382 which communicate ~etween conduit 378 and lands 372 and 376, res-pectively, at the surface of shaft 43. Lubricating fluid can be communicated to conduit 378 through a conduit means 379 mounted in the en~ of conduit 378 and connectible to lubricating pump 136, shown in ~IGo 2A~ Journalled on land 372 of shaft 43 and abuttin~ shoulder 370 is forward gear 384 of driven gears 44. This forward gear is freely rotatable about countershaft 43 and is in continuous engagement with driver forward gear 238 on shaft -- 34. Pressed on land 376 of shaft 43 is a bearing assembly 388 on which is mounted r~verse gear 390 o driven gear means 44. This gear 390 is freely rotatable about countersha-Et 43 and continuously engaged with reverse idler gear 41 of FIG. 1 of gear means 40 as known in the art. Slidably mounted on toothed ring 375 is synchronizer 46 that defines an annular groove and which synchronizer 25 46 is slidably engageable with either forward gear 384 or reverse gear 390. Synchronizer 46 also has a neutral position between these forward and reverse gears 384, 390 and is slidable by a gear seleetion fork 392 positioned in ~roove 394 defined by synchronizer 46. Synchronizer 46, at engagement with either forward 384 or reverse 390 gears -transfers power thro~lgh countershaft 43 to ring gear 54 mounted on the differential assembly 50 Qf the final drive assembly 20. Power is transferred to an axle or wheel arrangement as known in ~he prior ark and as illustrated in FIG. 1.
FIGS. 4 and 4A illustrate a part of the laminated clutch disc assem~ly 306 where the clutch disc 336 is a single narrow annular plate.
Disc 336 has opposed surfaces 337 and 339. Affixed to each of these surfaces 337,339 is a resilient material îayer, 341 and 343, respectively, such as Armstrong Cork Company~ 5 NC-711 material, which is a cork and neoprene composition. Mounted on ana affixed to each of these energy-absorbing material layers 341 and 343 is a friction facing material - - layer 338 and 340, respectively. This laminated clutch structure is generally very narrow in width, that is, on the order of 0.180 to 0 192 inch noted as dimension "x". Each of these resilien~
layers 341,343 is at least as thick as the thickness of the friction layexs 338 and 340, and preferably twice as thick as the friction layers.
FIG~ 5 illustrates a segment of an engaginy face of the friction facing material 33B or 340 on the clutch disc assembly. As shown, a pattern of oil grooves 345 is deEine~ on the friction facin~
layers. The result appears as a waffle pattern, that }s, equal surface areas, genPrally rectangular islands 353 of at least one-twenty fifth square inch in surface area. Clutch disc assembly 306 laminated structure has an inner periphery 355 and 7~
an outer periphexy 357 ana the friction material layers are disposed between these peripheries Islands 353 are clustered in groups which appear as arcuate seyments~ These arcuate segements define tapered channels 351 therebetween.
Each channel 351 has a given dimension at inner periphery 355, and the channel tapers, becoming gradually narrower as it extenas to outer periphery 357. At the outer periphery~ the channel width is reduced to a very small dirnension, of the order of one to three hundredths of an inch in the illustra~ed e~bodiment~ F.l.uid communication ports 354 are proviaed in clutch disc 306 providing a passage for cooling oil to inner periphery 355 of the friction material layer. From this location .. the cooling oil enters the throats of channels 351, which in turn communicate with grooves 345 of friction surface layers 338 and 340. Channels 351 appear as discontinuities in the otherwise continuous cross-hatched or waffle pattern ~n these friction surfaces.
In accordance with an important aspect of the invention, the depth of grooves 345 is at least twice the thicXness of friction layer 338 or 340.
This added depth provides a much greater volumetric flow ~or cooling fluid than is otherwise possible, with a consequent increase in cooling effectiveness.
To provide the requisite volumetric flow, grooves 345 extend into the resilient material layer~ If the resilient material layer is as thick as the friction material layer, the grooves extend -~hrough substantially all of the resilien~ layer.
In a preferred embodiment, the resilient layers are substantially twice as thick as each of the friction material layers. In this case the grooves 345 extend completely through the fric-tion material layer (338 or 340~ and through substantially one-half the resilient layer (341 or 343~. The ooolant fluîd ~low can be waste fluid from the high pressure control line diverted through the clutch coolant conduit 346 before its return to a sump., This large volume of waste oil is transferred through the extra deep grooves of the clutch friction facing and resilient layers, to provide much more effective cooling than is accomplished with conventional clutch structures. The coolant is transferred to conduit 346 through a large, , about three-quarters of an inch deepl ditch at ' less than one PSI pressure.
Transmission mechanism 10 is responsive to a ,control system 22 signal. The mechanism 10 provides a slippable starting clutch 16 that is fluid cooled and fluid pxessure actuated. The variable pulley system 14 of mechanism 10 is likewise fluid operated. At prime mover 12 start-up~ the con-tinuously variable pulley transmission (CVT~ 14 is as shown in the upper halves of pulley5 30 and 36 in FIG. 2, that is, where the belt 42 is at its bottom travel or low belt ratio in the driver pulley assembly 14 and the engine flywheel 26 is affixed to prime mover 12 as in FIG. 1. ~otational velocity is transmitted to driver pulley assembly 7~
30 by shaft 24 and thereafter throuyh belt 42 to - driven pulley assembly 36. Driven pulley assembly 36 continuously drives shaft 34, which is affixed to fixed pulley sheave 150, and to clutch cover plate 300 at the hub 310 with locknut 3167 Clutch 16 engagement proviaes a driving connection to synchronized forward-reverse di-rectional gear means 18 from pulley system 14.
The use of gear means 18 obviates the necessity to change belt direc~ion~to provide a change of direction to the final drive assembly 20.
Driving power from clutch 16 is provided to the driver gears 40 of forward-reverse gear means 18 through sleeve 240 which is mounted on and rotatable about shaft 34. Forward gear 238 is a~fixed to sleeve 240 and is con-ti.nuously engaged to forward gear 384 of the driven gears 44 of gear means 18, which driven gears 44 are mounted on and freely rotatable about countersha~t 43.
Drivingly mounted on sleeve 240 is a reverse gear 26~ of driver gears 40 of gear means 1~ which, in conjunction with an idler gear 41, continuously engages reverse gear 3~0 of driven gears 44 ~f ~ear means 18 which is bearing-mounted on counter-shaft 43 and forms a revexse gear arrangementknown in the prior art. Mounted on land 264 of reverse gear 262 on shaft 34 is a parking sprag 266 which is engageable at the stoppea or park position, and such gear engagement is well known in the pxior art. Synchronizex 46 is splined on ring 375 which is rigidly splined on countexshaft 43. The synchronizer is operable by shifting fork 392. The synchronizer 46 is positioned between and slidabl~ engageable with either the forward or reverse gears of driven gears 44. At synchronizer 46 engagement, as drive is being provided through engaged clutch 16, power is transmitted to the final drive assembly 20 in either a forward or reverse direction.
At transmission idle the prime mover 12 is driving in.put pulley 30 through a flywheel 26, vibration damper 28, and drive shaft 24. As sho~n in FIG. 2A, upper halves of pulleys 30 and 36 are shown în low belt ra~io (iOe., driver pulley 30 at lS maximum gap opening and belt 42 at closes~ ra~ius to drive shaft 24). Pulley~30 is utilized ~o control the belt position or ratio and not belt tension or output torque of the drive train. The change of width between fixed sheave 66 and movable sheave 68 of pulley 30 provides the change in belt ratio in response to $he transmission control means 22. This ratio control in the case shown in FIG. 2A, is provided for b~ an introduction o~ a fluid to sealed chamber 114, such as from a fluid ~5 supply means communicating with fluid passage 74 through insert 130 therein to passage 76 t chamber 98 and passage 88. A change in fluid volume into chamber 114 will proportionally move sheave 68 to reduce the sheave gap. As belt 42 travels from the inner radius of pulley 30 to the outer radius, ~9~
the transmission belt ratio changes from low to high with a range of about 5.4 to 1.
Purnp 136 is a*fixed to shaft 24 and only provides lubricant to the various wearing parts of the transmission at a rela-tively low pressure, that is in tlle range of a~out 20 psi. Con-trol fluid for chamber 114 passes through a counter-drilled hole 141 of pump 136 in the face of cover 138 and thus to *luid passage 74.
Output ariven pulley 36 is also fluid operative, however, as driver pulley 30 sheave gap decreases the driven pulley 36 sheave ~ap increases, and in FIG. 2A this implies that ~elt 42 would proceed from the outer radius to the inner radius of pulle~ 36. The sheave gap of the driven pu7ley 36 is determined by the position of movable sheave 68 of driver pulley 30 through belt 42. Control 1uid, at a line pressure controlled by control means 22, is freely communicated to control fluid cavity 224 o~ driven pulley 36 throush inser-t 1560 through hole conduit 154, passage 174, cha~ber 200 and passage 1~4. The piston area of movable sheave 152 within cavi~y 224 is noticeably smaller than its counterpart of driver pulley 30~ Control fluid in cavity 224 is bled to *luid cavi-ty 228 through orifi.ce 218 in piston flange 208. Fluid is transferred to cavity 228 to balance the centrifugal component of the total pressure on either side of flange 208 thereby avoiding a centri*ugal thrust on sheav~ 152. The movable sheave :l52 has a bias spring 226 acting on it and biasing the sheave to minimize the sheave gap width The through-hole conduit 154 provides a transfer means for ~ontrol fluid for slipp~ble starting clutch 16, which is engaged through fluid pressure in cham~er 332, see FIG. 3. The force of the Belleville spring 308 of clutch 16 ten~s to maintain pressure plate 302 in the non-contacting or open position. When the fluid pressure in cavit.~ 332 is sufficient to overcome the Bellevill~
spring 3~8 i-orce, pressure plate 302 is pressed - into contact with friction ~acing 340 to thereaftex engage driven plate 304. Coolant fluid is supplied through control means 22 and conduit 346 to cooling fluid cavity chamber 348 of clutch 16~ At clutch engagement pressure plate 302 contacts friction Eacin~ 340 to dri~ingly engage driven plate 304.
Driving power is thus provided to hollow sleeve 240 of driver gears 40 through disc 336, annular ring 342 and spline member 344~ Therea~ter, rotational motion is communicated to forward gear 233 and reverse gear 262, which gears are rigidly connected, to each other, ana through which shaft 34 extends~ and about which shaft 34 forward~
reverse gears 238, 262 are ~reely ro~atable.
Forward or reverse drive direction, or neutral, if desired, is selectable by operation oE synchronizer 46. The synchronizer 46 position is slidably operable by the fork 392 and rail 47, as known in 3Q the prior art. The forward, reverse gears 334 J
390 on countershaft 43 are in constant engagement with matiny forward year 238, on shaft 340 or idler 41, respectively~ At synchronizer 46 en-gagement rotational motion is transferred to th~
final drive assembly 20, which assembly includes elements such as a differential 50 and drive axle 56 as known in the prior art~
In the operation of this transmission mechanism the pulley system 14 is in constant unidirectional rotary motion whenever prime mover 12 is operating.
All power to the final drive assembly 20 must be communicated from the pulley system 14 through the slippable starting clutch 16, and forward-reverse gear means 18~ In this arrangementJ the con-trol means 22 controls fluid line pressure in passage 154 and fluid volume in chamber 114 based on engine (input~ speed, output speed, throttle (not shown) position and year shift lever 47 position~
The volume of oil in pulley 30 is controlled by means 22 in response to each throttle position to maintain a constant input RPM. For example, during acceleration at one-quarter wide open throttle, means 22 may be progra~ned to maintain a fixed input ~PM, such as 1500 RPM input speed while the belt ratio is be.ing varied Erom low to high ratio. Conversely, at that throttle opening during a condition of vehicle speed reduction~
such as from climbing a grade, the input RPM will be maintained by changing the belt ratio toward low through a discharge of fluid from pulley 30.
In the starting mode the control means 22 increases the fluid pressure in clutch 16 as a function of the engine input RPM ~for eY~ample, as the square o the illpUt RPM). Therefore, at a given throttle opening, a constant torque and a constant RPM will be maint~ined at clutch pressure plate 302 and the ve~icle will accelerate from rest at a constant rate~ With the increase in vehicle speed t the RPM
of the driven plate increases a~ a fixea (geared) ratio until it reaches the cons~ant RPM of the clutch pressure plate 302, which aefines the ena-point of clutch slip, or the end of the startingmode.
FIG. 6 shows the increase of clutch driven plate speed as a ~unction of vehicle speed ~n a curve 600. As shown there is a corresponding - 15 vehicle speed (in miles per hour or MPH) for each particular dri~en plate speed ~in revolutions per m;nute or RPM). Curve 600 indicates that vehicle speed and clutch pressure plate speed intersect at a point 602. At that point, the starting clutch is at the end of its slipo From the origin until the end of clutch slip, th~ angular speed o~ clutch reaction plate 304 rises proportionally with vehicle speed, and this rise is dependent upon gear ratio, not belt ra-tio. The pr~ssure 25 or driver plate 302 is rotating at a constant speed (at a given throttle opening~.
Also in the s~arting mode at the first momPnt ~efore a vehicle has attaine~ a measurable velocity the input torque when plotted as a predetermlned function of engine speed can be/ for example, a paraholic curve similar to a hydrokinetic device or a centrifugal clutch~ In ~IG. 7 t curve G04 is a parabolic function showing the variatlon of input clutch torque (in ft.-lbs.~ or net pressure (in psi) on clutch pressure plate as a function o~
engine speed, where the abcissa commences at a value connoting engine idle speed, rather than zero RPM. ~lso the pressure at engine idle speed is controlled to cancel the opposing force o~ Belleville spring 308 so the net pressure on the clu-tch pressure plate is zero at normal engine idle speedg and consequently creep is avoided~ Creep is defined as the power transfer through the drive train at stall speed sufficient to overcome rolling resistance~
A second general ~unction 606 with a maximum - value at point 608 is also shown. This second function 606 represents the net engine torque at wide open throttle as a function of engine spee~.
The intersection of curves 604 and 606, at poin~
610, indicates the stall point. This is not a different stall point than that previously noted, but explains the same point utilizing dif-Eerent parameters. The continuation of the parabolic curve 604 abo~e the stall point 610 represents the reserve pressure at the clutch pressure plate.
The input tor~ue beyond point 610 is limited to the maximum engine torque 60~ The control means 22 accordingly limits the rise in pre~sure to a predetermined value 612 to provide a controlled reserve pressure slightly above the wide open throttle tQrque requirement. Correspondingly r a suitable reserve pressure is provided at other torques down to about 25~ of the torque at wide open throttle. This mlnimum value also correspon~s to the max;mum engine ~raking torque. This provides a means to protect pulley system 14 from incurring slip and reduces ~elt 42 loading that would o-therwise tend to fatigu2 the bel-t.
Clutch 16 is a liquid cooled (wet~ starting clutch.which is slippable in the starting mode as torque is provided to the final drive assembly 20 At clutch 16 dlsengagement the fIuid pressure in chamber 332 is removed and the Belleville spring .. ... ;.. ... .
. ~ 308 acts to retract pressure plate 302 to the disengaged position. This reaction is almost instantaneous, that is, on the order o~ one-tenth (0.1) second.
Curve 614 in FIG. 8 is generally similar -to curve 604 in FIG. 7. Curve 614 will be used, in conjunction with representative values rounded of~
to whole numbers for ease of cvmprehension, and these values do not limit the present invent;on.
Curve 614 shows clutch torque p:Lotted as a function o engine speed. In this example, wide open th.rottle in the starting mode is indicated at stall point 616, correspond~ng to 2100 RPM and a clutch torque load of 140 ~t.-lbs. At this 2100 RPM engine speed, if the bel-t is at a 1:2 under-drivP ratio/ at point 616, at this low belt ratio 8~
there is effectively a 140 ft.-lbs. clutch torque.
However, the clutch torque for a 2:1 overdrive ratio, at this same throttle opening, is effectively 35 ft.-lbs. In this example, the engine RPM for the 35 ft.-l~s. clutch torque on the curve is denoted at point 618, corresponding to 1300 RPM, which becomes the new stall point, and at this high belt rato of 2:1, point 618 also represents the lugging limit.
~ In other words lugging below this engine speed is inherently avoided along with the harshness or torsional disturbance associated with lug~ing at very low speed particularly so with ~our cycle engines~ At vehicle speeds below the lugging ~5 - limit, the clutch begins to slip and a torsional disturbance associated with such lower speeds will not be transmitted through the clutch. Relow the lugging limit engine speedl the control means 22 will again downshift and the engine speed will increase even at a lower vehicle speed tc thereby remain above the lugging limit.
In a conventional CVT with a startin~ device on the input side o~ the belt stall point is the same in both high and low belt ratios at any given throttle opening, and it is then necessary to add a lock-up device in order to operate the engine in the more efficient speed range below the stall point and this device still does not provide an inherent lugginy limit.
The use of a slippable starting clutch and a forward-reverse gear mechanism provides a compact 7~
arrangement o~ elements to provide power transferO This mechanism is in lieu of multiple clutch packs or heavier, more complex planetary ~ear assemblies as shown in U.S.
Patent 4,342 r 238, issued August 3, 1982.
Clutch 16 is cooled through cooling paths cut in f~iction facings 338,340 and resilient layers 341,343, respectively. This cooling is provided by fluid passing through the waffle pattern on the friction facing. The coolant fluid is waste fluid, such as oil~ diverted from a low pressure return line o~ control means 22. This fluid does not, therefore, require added pump capacity for the high pressure fluid line and as fluid conduit 349 is a relatively large passage, added coolant through the clutch avoids excess back pressure on the control means 22 These large passages permit large volume flows at low pressures thereby obviating high fluid pressures from a pump source and providin~ greater cooling capacity than is presently known.
In the illustrated embodiment, driven pulley 36 is in a centrifugally balanced condition, that is the centrifugal component of the fluid force on either side of flange 208 is virtually equal, thereby avoiding an im-balance Erom a centrifugal pressure effect within chamber 2240 The clamping force and, therefore, the tension on belt 42 is provided by khe fluid pressue ~n chamber 224 and bias spr~n~ 150. This clamping force varies with the ~luid pressure controlled only to -that pressure required to limit belt creep at a ~iven torquer In the prior art it has been the practice to maintain a lar~e fixed force on the belt 42, regardless of torque input, to thereby ~void belt slip. The prior art overloaded belt, at part en~ine load, increases belt fatigue and ~riction losses, and is an added load on the engine or 1uid pressure supply system.
mab/
The attainment of output speed and final gear ratio is through the single paper plate clutch where clutch 16, clutch disc 336 and pressure plate 302 are running at the same speed, having arrived at a locked up state without a jump or lurch, and without a speed differential at lock-up. Those goals were attained through the use of a forward-reverse gear mechanism in con.junction wi-th a wet clutch while also reducing the number of parts and total weight of the assembly~ Such advantages are very important to the automotive industry wherein government regulations require improved fuel efficiency; such an improvement in efficiency is directly proportional to weight losses. In addition, th.s is the most compact automatic transmission currently available. The economies of reducing the number of parts in any assembly while accom-plishing the same task provides cost savings of both material and assembly laborv . , ~ ... .
The above~described transmission mechanism is also described and is claimed in above-identified parent appli-cation Serial No. 400,560 The operability of this transmission clearly obviates the use of multiple clutch packs and planetary gear sets. Furt.her the clutch as disclosed, gives an almost instantaneous disengaging response just by releasing the fluid pressure from the clutch. The use of the combination of elements disclosed gives the user improved cost econo-mies, faster :response time, bettex control, less wear of CVT elements and better fuel economy without a creep con-dition and without a garage shift thump and also proyides better u-tili~ation of fluid with reduced output requirements on the fluid pump~
mab/J
Claims (3)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A fluid cooled clutch including a generally annular laminated clutch disc assembly having an inner and an outer periphery which disc assembly comprises a central disc with opposed surfaces, a resilient material layer affixed to each surface, a friction material layer affixed to each resilient layer where each resilient layer is at least as thick as the friction material layer, and a pattern of grooves is provided in the friction material layer, which grooves extend completely through the friction material layer and through substantially all of the resilient layer, thus providing a path for coolant fluid flow in the laminated structure which is substantially greater than that of a grooved friction layer.
2. A fluid cooled clutch as claimed in Claim 1, and further characterized in that a plurality of channels is provided in the friction material layer and resilient material layer of a depth substantially equal to the depth of the grooves, which channels extend from the inner periphery to the outer periphery of the friction material layer, with each channel tapering from a given dimension at said inner periphery to a dimension smaller than the given dimension at the outer periphery, to transfer fluid to the grooves along the radial extent of the disc assembly,
3. A fluid cooled clutch as in Claim 1, wherein said grooves define islands of exposed friction material between said grooves, which islands or friction material are substantially at least one-twenty fifth square inch in sur-face area.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US257,283 | 1981-04-24 | ||
| US06/257,283 US4433594A (en) | 1981-04-24 | 1981-04-24 | Variable pulley transmission |
| CA000400560A CA1175258A (en) | 1981-04-24 | 1982-04-06 | Variable pulley transmission |
Related Parent Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000400560A Division CA1175258A (en) | 1981-04-24 | 1982-04-06 | Variable pulley transmission |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1190872A true CA1190872A (en) | 1985-07-23 |
Family
ID=25669643
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000438981A Expired CA1190872A (en) | 1981-04-24 | 1983-10-13 | Fluid cooled clutch |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1190872A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113864352A (en) * | 2021-10-21 | 2021-12-31 | 南昌航空大学 | Clutch suitable for short-distance vertical take-off and landing aircraft |
-
1983
- 1983-10-13 CA CA000438981A patent/CA1190872A/en not_active Expired
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113864352A (en) * | 2021-10-21 | 2021-12-31 | 南昌航空大学 | Clutch suitable for short-distance vertical take-off and landing aircraft |
| CN113864352B (en) * | 2021-10-21 | 2023-10-24 | 南昌航空大学 | Clutch suitable for short-distance vertical take-off and landing aircraft |
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