CA1150982A - Powershift synchronized transmission - Google Patents
Powershift synchronized transmissionInfo
- Publication number
- CA1150982A CA1150982A CA000389180A CA389180A CA1150982A CA 1150982 A CA1150982 A CA 1150982A CA 000389180 A CA000389180 A CA 000389180A CA 389180 A CA389180 A CA 389180A CA 1150982 A CA1150982 A CA 1150982A
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- Prior art keywords
- speed ratio
- shaft
- clutch
- gear
- countershaft
- Prior art date
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Abstract
ABSTRACT OF THE DISCLOSURE
Disclosed is a power shift transmission having torque converter, an input shaft driven by the torque converter, a countershaft in continuous driving relation with the input shaft, an output shaft having first, second, and third speed ratios journaled thereon and driven via the countershaft, a reverse speed ratio gear splined to the output shaft and driven via a gear on an idler shaft driven by the countershaft, a first friction clutch mechanism for connecting the first speed ratio gear to the output shaft, a second friction clutch mechanism for connecting the output shaft directly to the input shaft, a blocker-clutch assembly for coupling the second and third speed ratio gears to the output shaft, and an actuator assembly for shifting the blocker-clutch assembly into and out of coupling engagement. The friction clutches are momentarily engageable to relieve driving and coast mode torque on the blocker-clutch and to synchronize the blocker-clutch. An alternative embodiment of the transmission includes a torque converter driven shaft for driving the countershaft and a torque converter bypass shaft which is connected directly to the output shaft via the second friction clutch mechanism.
Disclosed is a power shift transmission having torque converter, an input shaft driven by the torque converter, a countershaft in continuous driving relation with the input shaft, an output shaft having first, second, and third speed ratios journaled thereon and driven via the countershaft, a reverse speed ratio gear splined to the output shaft and driven via a gear on an idler shaft driven by the countershaft, a first friction clutch mechanism for connecting the first speed ratio gear to the output shaft, a second friction clutch mechanism for connecting the output shaft directly to the input shaft, a blocker-clutch assembly for coupling the second and third speed ratio gears to the output shaft, and an actuator assembly for shifting the blocker-clutch assembly into and out of coupling engagement. The friction clutches are momentarily engageable to relieve driving and coast mode torque on the blocker-clutch and to synchronize the blocker-clutch. An alternative embodiment of the transmission includes a torque converter driven shaft for driving the countershaft and a torque converter bypass shaft which is connected directly to the output shaft via the second friction clutch mechanism.
Description
115~982 This invention relates to transmissions and, more specifically, to transmissions which are powershifted and synchronized.
This is a division of copending Canadian Patent A~pli-cation Serial No. 340,580, filed November 26, 1979.
This application is relat~l to copending Canadian ~pplications Serial Numbers 340,581, filed November 26, 1979; 340,582, filed November 26, 1979; 340,583, filed November 26, 1979;
and 340,5~5, filed ~ovember 26, 1979. All of these applications are assigned to the assignee of this application.
It i.s known in the art to selectively enc~age and disen-gage positive or ~aw type clutches to shift a transmission from one speed ratio to another. Positive clutches are pre-ferred in transmissions since they are compact and inexpensive :relative to friction clutches and a~e extremely reliable if they are synchronously engaged. Most of these transmissions are manually shiftedcmd employ a manually operated friction eluteh for d:iseonneeting the trallsmissioll input sha:Et Lrom a prime mover when shiEting from OllC' ratio to anot}ler. ",uch dis-conneetincl by the frieti.on elutc~ll })as the d.isadvalltac,le of inter-upting the driving conrlecL:i.on betwoen the prinle mover and the load conrle(-ted to t,he t~l-al-lsmission out:.l)ut sllat-. I~urther, whcn sueh transmissions are used in relati.vely hcavy vell:i.el,es, the vehi,ele op~rator must per:Eorm a double clutchincl manipulation of the friction clutch when shifting from one ratio to ano-ther.
When double elutehing, the operator must momentarily disengage the frietion eluteh to relieve torque on the positive eluteh .' to be disengaged, then momentarily reengage the frietion , ~
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clutch to synchronize the positive clutch to be engaged, asld then momentarily disengage the friction clutch prior to ensagement of the positive clutch to minimize shock loading. Further, when the friction clutch is momentarily ~eengaged, the vehicle operator must either increase or decrease the prime mover speed to bring the positive clutch to synchronism. If the operator is unskilled or if the vehicle is moving slowly and/ox if the vehicle is on a steep grade, it is not uncommon for a shift to be missed or for the positive clutches to be abused due to asynchronous engagement.
Many attempts have been made to adapt the above type of transmissions to automatic or semiautomatic controls to negate the above problems. One such attempt, as disclosed in U.S. Patent 3,589,4g3, proposes positive clutches for engaging the several speed ratios, a first friction clutch for connecting the several speed ratio gears to a prime mover, a second friction clutch for connecting the transmission output sha~t directly to the prime mover and synchronizing the positive clutches during upshifting, and a semiautomatic control system for controlling the sequential operation of the friction and positive clutches when a shift control lever is rnoved from one ratio position to another. When the lever is moved in an upshift sense, thc control automatically provides power upshifting and synchroni~ing by momentarily or partially disengaging the first ~riction clutch and by momentarily or par-tially engaging the sccond friction clutch.
When the lever is moved in a downshift sense, the control automatically provides a partial power downshifting by manipulating engagement and disengagement of the friction clutches, but synchronizing must be provided by engine speed manipulation. During both upshifting and downshiftir.g, the clutch teeth of the positive clutch to be engaged are moved into abutment with each other prior to synchronism therebetween, thereby exposing the positive clutches to asynchronous engagement.
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According to the present invention there is provided a powershift transmission which has a housing, input drive means, an output drive shaft, and at least one countershaft mounted for rotation in the housing, the countershaft being in constant driving relation with the input drive means. Low and intermediate speed ratio means are provided, each ratio means including a gear pair in constant mesh, one gear of each pair being permanently fixed to one of the shafts and the other gear of each pair being rotatably mounted on the other shaft.
A jaw clutch means is operative when engaged to connect the rotatably mounted intermediate speed ratio gear to the other ~ shaft. A first friction clu-tch is operative when engaged to connect the rotatably mounted low speed ratio qear to the other shaft independent of the intermediate speed ratio gear pair and the jaw clutch. A second friction clutch is operative when engaged to interconnect the input drive me~ans ~Ji th the output shaft for providing a high speed ratlo independent of the other speed ratio means and the otl-er clutches.
~ccordinq to a spc~cific cml)odiment o~ the invention there is provi(led a trallsmission which ;nclnclcs an input shaft and an output shaf-t alld at lcast one co~ crs~aft and ratio change means operative to provide at least lcw, intermediate, and high speed ratio chall~es betwec?n the input and output shafts via the countershaft; the ratio chanc3e means inc]udes a low and an intermediate speed ratio gear mounted for rotation about one of the shafts, first and second jaw clutch members operative when engaged to couple the intermediate gear to the one shaft and to provide the intermediate speed ratio, a first friction clutch fully engageable to couple the low gear to the one shaft and to provide the low speed ratio cg/~
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and momentarily engageable during downshifting into the inter-mediate speed ratio to synchronize the jaw clutch members, and a second friction clutch fully engageable to couple the input shaft directly to the output shaft to provide the high speed ratio and momentarily engageable during upshifting into the intermediate speed ratio to synchroni~e the jaw clutch members.
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BRIEF DESCRIPTION OF_THE DRAWINGS
The transmission of the instant invention is shown in the accompanying drawings in which:
FIGURE 1 i5 a partially sectioned view of the transmission, looking along line 1-1 of FIGURE 2;
FIGURE 2 is an end view of the rear housing member of the transmission;
FIGURE 3 is a partially sectioned view of a torque converter shown in FIGURE l;
FIGURE 4 is a fully sectioned view of a portion of the transmission ratio gearing, clutches, and an actuator-, FIGURES 4A and 4B are detailed views of a portion of a blocker-clutch in FIGURE 4;
FIGURE 5 is a fully sectioned view of another portion of the transmission ratio gearing, clutches, and an actuator; and FIGURE 6 is an alternative embodiment of the transmission torque converter and input shaft.
DETAILED DESCRIP'rION OF THE DRAWINGS
__ _ ~ _ ___ Looking now at FIGURES 1 and 2 and in particular FIGURE 1, therein is shown a powershift transmission 10, partially sectioned along line 1-1 of FIGURE 2. The transmission is intended for use in a land vehicle but is not limited to such use. The transmission is preferably automatically shited by an unshown control system which forms no part of the instant invention. The transmission includes a housing assembly 12, a fluid coupling or torque converter assembly 14 which may be directly driven by an unshown internal combustion engine, an input shaft 16, an output shaft assembly 18 including an output shaft 20, at least one countershaft assembly 22 including countershaft members 24 and 26 splined together at 27, a friction clutch assembly 2 8, a blocker-clutch assembly 30, an actuator assembly 32, and a reverse gear assem~ly 34 including an idler shaft 36.
1~5~182 In describing transmission 10, its leftward portion, as shown in FIGURE 1, will be referred to as the front and its rightward portion will be referred to as the rear.
Ilousing assembly 12 includes a front housing member 38, having a bell housing portion 38a integrally formed therewith, a rear housing member 40, and an intermediate plate member 42. Members 38, 40, and 42 are secured together via a plurality of bolts 43. A flange portion 38b of bell housing 38a provides means for securing the transmission to the rear of an unshown engine. The front housing member carries bearings 44 and 46 for rotatably supporting input shaft 16 and countershaft 24. The rear housing member carries bearings 48, 50, and 52 for rotatably supportiny output shaft 20, countershaft 26, and idler shaft 36.
Looking at both FIGURES 1 and 2, the true position of countershaft 26, idler sh~ft 36, and actuator assembly 30, relative to output shaft 20, may be gleaned from the position of bosses 40a and 40b which carry bearings 50 and 52 and from a boss 40c which defines a portion of a cylinder housing 54 of the actuator assembly 32. Inter-mediate plate 42 includes a through bore 42a for the passage of output shaft 20 and through bores 42b and 42c which carry bearings 56 and 58 for rotatably supporting countershaft 26 and idler shaEt 36. Rear housing me~er 40 further includes a power takeoff pad 40d and a flange 40e for the attachmellt o~ an oil pan 60, shown only in FIGURE 2.
Looking now at FIGURES 1 and 3 and in particular FIGURE 3, torque converter assembly 14 includes an impeller 62 driven by a shroud 64, a turbine 65 hydraulically driven by the impeller and in turn drivingly fixed to input shaft 16 at 66, and a runner or stator 68 which becomes grounded to housing member 38 via a one-way roller clutch 70 carried by a sleeve 72 fixed to the housing member. The rear side of shroud 64 is fixed to ~5~9~32 a sleeve 74 which rotatably supports the rear of the shroud and drives a pump 76. Pump 76 may be a well known crescent gear pump for pressurizing the torque converter, for lubricating the transmission, and for providing pressurized fluid to engage friction clutches and actuators in the transmission.
Looking now at FIGURES 1 and 4 and in particular FIGURE 4, input shaft 16 is integrally formed with an input gear 16a which is in constant mesh with a countershaft gear 78, an annular flange 16b for connecting the input shaft to friction clutch assembly 28, and a recess 16c carrying a bearing 80 for rotatably supporting the front end of output shaft 20. Friction clutch assembly 28 includes a clutch mechanism 82 for connecting the input shaft directly to the output shaft and a clutch mechanism 84 for connecting a low or first speed ratio gear 86, driven by the countershaft, to the output shaft.
Clutch mechanism 82 includes a housing member 88 splined to shaft 20, a set of friction disks 90 slideably splined to internal splines 88a defined by member 88, a set of friction disks 92 slideably splined to external splines 16d defined by annular flange 16b, a piston 94 for squeezing the dis~s together in response to pressurized fluid being introduced into a chamber 96 de~ined by ; 25 housing member 88 and piston 94, and a set of return springs 98 for r~tracting the piston. ~lousing member 8 is axially retained by a shoulder 20a de~ined by a step in shaft 20 and a snap ring 100 which also r~tains a radially extending flange 192 having springs 98 reacting thereagainst. Pressurized oil for actuating clutch 82 is introduced into chamber 96 via a passage 104 in housing 88, passages 106, 108, and 110 in shaft 20, and passages 112 and 114 in intermediate plate 42 and in an annular rim portion 42d which extends the axial interface of bore 42a with shaft 20. Passage 114 is connected to Z
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an unshown control system which is selectively operative to provide the pressurized oil. Passages 108 and 114 are sealed at their for~Yard and rearward ends, respectively, by interference fit balls 116 and 118. Passages 109 and 106 are sealed at their respective interface with member 88 and bore 42a via pairs of seals 105 and 107. Oil for lubricating bearing 80 and the disks of clutch 82 flows through a passage 120 in intermediate plate 42, passages 122, 124, and 126 in shaft 20, and a plurality of ` 10 passages 128 in flange 16b. Passage 124 is sealed at its forward end by an interference fit ball 127.
Clutch mechanism 84 includes a housing member 130 rotatably supported on shaft 20 via a bearing 132, a set of friction disks 134 slideably splined to internal splines 130a defined by member 130, a set of disks 136 slideably splined to external splines 88b defined by housing member 88, a piston 138 for squeezing the disks together in response to pressurized oil being introduced into a cha~ber 140 defined by housing member 130 and piston 138, a set of return springs 142 for retracting the piston, and a hub portion 130b defined by housing member 130. Low ratio gear 86 is splined to hub portion 130b and axially retained thereon by a snap ring 141. Housing member 130 is axially retained ~or rotation relative to housing member 88 and rim portion 42d via thrust bearings 144 and 146. Sprillgs 142 react against a radially exterldincJ
flange 148 secured to member 130 via a snap ring 150.
Pressurir~ed oil for actuating clutch 84 is introduced into chamber 140 via passages 152 and 154 in hub portion 130b and passages lS6 and 158 in rim portion 42d and intermediate plate 42. Passage 156 is sealed at its interface with hub portion 130b via a pair of seals 160.
Passage 158 is sealed at its rear~Yard end by an inter-ference fit ball 162. Oil for lubricating bearings 132, 144, and 146 and the disks of clutch mechanism 84 flows '' , ~15~g8~
through passages 124, 164, and 166. Passage 158 is connected to the unshown control system which is selectively operative to provide the pressurized oil.
Looking now in the area of blocker-clutch mechanism 30, therein are three gears, a reverse speed ratio gear 168 splined to shaft 20 and retained against forward movement by a shoulder 20b and first and second inter-mediate speed ratio gears 170 and 172 supported for rotation on shaft 20 by sleeve bearings 174 and 176. Gears 170 and 172 each include an axially extending sleeve portion or jaw clutch member 170a and 172a which each have external jaw clutch splines 170b and 172b. Gears 170 and 172 are axially spaced apart by a sleeve 178 splined on its I.D. to shaft 20 and retained against axial movement by a shoulder 20c and a snap ring 180. Gears 170 and 172 are ~xially retained on their forward and rearward sides, respectively, by thrust bearings 182 and 184.
Blocker-clutch mechanism 30 includes the jaw clutch members 170a and 172a, a jaw clutch member or means 186 having internal jaw clutch splines 186a slideably splined to external splines on sleeve 178, a radially extending flange portion 186b integrally formed wi-th member 186, three circumferentially positioned pins 188 (one of which is shown) extending parallel to the axis of shaft 20 and through holes 186c in flange portion 18Gb, two friction cone-clutch members 190 and 192 rigidly secured tocJether by pins 188, two friction cc~ne-clutch members 170c and 194 engageable with friction members 190 and 192 and each fixed for rotation with its respective gear, and three circumferentially positioned split pins 196(one of which is shown) alternately spaced between pins 188 and extending parallel to the shaft 20 and through chamfered holes 186d in flange portion 186b.
Looking momentarily at both PIGURES 4 and 4A, each split pin includes a pair of semicylindrical halves 198 ~L~S~82 _9_ and 200 having a major diameter less than the I.~. of holes 186d when squeezed together, semiannular grooves 198a and 200a with ch~nfered ends, and a leaf spring 202 for biasing the annular grooves apart to engage the groove ch~nfers with the hole chamfers. Halves 198 and 200 abut at their ends against end walls l90a and 192a of blind bores in friction members 190 and 192.
Looking momentarily at both FIGURES 4 and 4B, each hole 186c extends parallel to the axis of shaft 20 and includes oppositely facing square shoulders 186e and 186f positioned normal to the axis of shaft 20. Each pin 188 includes a major diameter 188a less than the I.D. of its respective hole 186c and a groove or reduced diameter portion 188b defining oppositely facing blocking shoulders 188c and 188d which are parallel to square shoulders 186e and 186f.
When blocker-clutch mechanism 30 is in the disengaged or neutral position, as shown, gears 170 and 172 are free to rotate relative to shaft 20. When it is desired to couple either gear to the shaft, actuator assembly 32 applies an actuating or engaging force to flange portion 186b to effect movement of jaw clutch member :l86 toward the jaw clutch members 170a or 172a. If the engaging force is to the left, initial movement of the flange portion is transmitted through split pins 196 via leaf spring 202 and the chamfered sho~lders to e~ffcct resilient engagement of friction members 190 and 170a. This resilient engagement (provided gcar 170 and shaft 20 are rotating asynchronously) causes the reduced diame-ter portion 188b of pins 188 to move to one side of holes 186c, whereby square shoulders 186e engage blocking shoulders 188c to block engagement of jaw clutch member 186 with jaw clutch member 170a until gear 170 crosses synchronism with shaft 20. Since shoulders 186e and 188c are normal to the axis of shaft 20 and the direction of movement of ~5~9B2 jaw clutch member 186~ the shoulders provide a positive or infinite block which is independent of the forces on the shoulders and the frictional torque between friction clutch members 190 and 170c, ther~by preventing asynchronous engagement of the jaw clutch members should the design frictional torque between the friction members be slow in developing due to oil on the friction surfaces or should the design frictional torque fade due to a change in the coefficient friction of the surfaces.
Actuator assembly 32 includes a hydraulic actuator 204 and a spring box 206. Actuator 204 includes the cylinder housing 54 defined by rear housing member 40, cylindrical bore portions 208a, 208b, 208c, and 208d de-fined by a stepped bore 208 having shoulders 208e, 208f, and 208g, an end wall 210 abutting shoulder 208e and retained thereagainst by à snap ring 212, a piston rod 214 disposed in bore 208 for sliding movement parallel to the axis of shaft 20 and radially spaced therefrom, a piston 215 integrally formed with the piston rod for sliding rnovement in bore portion 208c, a piston 216 disposed for sliding movement within bore portion 208b and on piston rod 21~, and a sleeve or stop member 217 slideably supported by piston rod 214 and interposed between the pistons. Piston rod 214 includes an end portion 214a slideably disposed in bore portion 208d for support purposes and an cnd portion 214b cxtcn~l;ng through end wall 210. Pistons 215 and 216 divide hore portions 208b and 208c into three fluid chambers. The mutually facing sides 215a and 216a oE the pistons in part define a first fluid chamber 218 and the distal sides 215b and 216b of the pistons in part define second and third fluid chambers 220 and 222. Passages 224, 226, and 228 provide means for porting oil to and from the fluid chambers via the unshown control system. Conventional seals prevent oil leakage of the cylinder and by the pistons. The seals 1 3LS~8Z
.
may be Quad-X Brand Seals obtainable fro~ Minnesota Rubber Company.
Spring box 206 includes a sleeve 230 concentric to end portion 214b of the piston rod 214, annular bearing rings 232 and 234 slideably supporting the sleeve on the end portion, snap rings ~36, 238, 240 and 242 defin-ing stop means, a pre-loaded coil spring 244 interposed between the bearing rings and ~iasing the rings apart - and into engagement with the stop means defined by the snap rings, and a shift fork 230a integrally formed with the sleeve. Shift fork 230a extends outward around the periphery of flange portion 186b and connects the flange portion to the sleeve in a conventional manner, as may be seen in FIGURE 1. searing rings 232 and 234 are spaced apart as far as practicable to minimize shift fork cocking forces between the sleeve and end portion. Further, each ring includes concentric sleeve portions, such as sleeves 232a and 232b, which define an annular recess for receiving the spring ends and for increasing -the outer and inner circumferential bearing surface of the rings, thereby lowering the surface forces on the bearings to reduce wear.
Looking now at FIGURES 1 and 5 and in particular FIGURE 5, countershaft assembly 22 incl-lcles the counter-shaft mem~ers 24 and 26, the gear 78 fixed for rotationwith shaft 24 and in conskant mcsh with ;n~ut cJear 16a, the splined connection 27 connccL-iny shaft 24 to shaft 26, gears 246, 248, and 250 fixed for rotation with shaft 26 and in constant mesh with gears 86, 170, and 172, respectively, and a power take-off gear 252 also fixed for rotation with shaft 26.
Reverse gear assembly 34 includes the idler shaft 36, a gear 254 supported for rotation about shaft 36 via a sleeve ~earing 256 and in constant mesh with gear 248, a gear 258 fixed for rotation with shaft 36 and in constant 3 15~8:~
mesh with the reverse speed ratio gear 168 when shaft 36 is in its true position as described in connection with housing assembly 12 and FIGUP~ 2, a positive clutch assembly 260 for coupling gear 254 with shaft 36, and a hydraulic actuator 262 for selectlvely moving the clutch into and out of engagement.
Positive clutch 260 includes a set of jaw clutch teeth 254a defined by gear 25~, a jaw clutch member 264 slideably splined to shaft 36, a set of jaw clutch teeth 264a defined by member 264 and engageable with teeth 254a, and an annular groove 264b which receives a shift fork 266.
~ ydraulic actuator 262 includes a piston 268a formed with or fixed to a rod 268 and disposed in a cylinder defined by rear housing member 40, an end plate 269 for closing the cylinder, and the shift fork 2~6 fixed to rod 268. Hydraulic sealing of the piston and cylinder is provided by seals in a conventional manner.
Passages 270 and 272 provide means for porting oil to and from the actuator via the unshown control system.
OPERATION
In reviewing the operation, it wlll be assumed that transmission 10 is installed in a land vehicle having an internal combustion engine coupled di~ectly to shroud 64 of the torque converter, and that a shift control system will automatically effcct shifting t:o l:hc dcsired speed ratios in the proper sequence. Such control systems are well known and are often made responsive to parameters such as engine load and vehicle speed. It will also be assumed that the shift control system includes a shift contro] selector which is selectively placed in a neutral position to disengage the transmission, in a drive position to effect forward movement of the vehicle, and in a reverse position to effect reverse movement of the ~15~32 vehicle. However, the shift control selector could have four forward drive positions corresponding to the four forward speed ratios of the transmission- in which case, the shift control system could be made operative to engage only the ratio corresponding to the selector position or sequentially upshift and downshift between the low speed ratio and the highest ratio corresponding to the position of the selector. The shift control systems referred to ~erein are by way of example only and do not form part of the invention herein nor are they purported to be preferred forms of shift control systems.
In the following operational description, friction clutch 82 and 84 will be referred to as being either fully engaged or momentarily engaged. When fully engaged, the clutch locks-up. When momentarily engaged, the clutch slips. To implement the slipping, the control system pressure for engaging the clutch may be reduced and/or supplied for such a short period that full engagement or lock-up is not reached.
With the shift control lever in neutral and the engine running, input shaft 16 is driven by torque converter assembly 14; countershafts 24 and 26 are driven at a speed proportional to tlle speed of input shaft 16 via gears 16a and 78; ratio gears 86, 170, and 72 are driven at speeds proportional to their respective counter-shaft gears 246, 248 and 250; and the co~trol system ports pressuri~ed oil to cllambers 220 and 222 of hydraulic actuator 204 to position rod 214 in the nc~ltral position as shown in the drawings. Further, output shaft 20 is completely disconnected from input shaft 16 and counter-shafts 24 and 26 since friction clutches 82 and 84, blocker-clutch assembly 30, and positive clu~ch 260 are all di5engaged.
Assume now that a vehicle operator places the shift control lever in the drive position and wishes to accelerate ~ IL5~
the vehicle in a forward direction to a speed which will cause the control system to sequentially power upshift through each of the four ~orward drive ratios of the transmission. When the shift lever is placed in drive, the control system fully engages friction clutch 84 by porting pressurized oil to chamber 140 thereby squeezing friction disks 134 and 136 together and connecting gear 86 to output shaft 20 via housings 130 and 88 of clutches 84 and 82, respectively.
When the sensed parameters indicate upshifting from the low speed ratio, the control system will operate to effect a power upshift from the low speed ratio provided by gear 86 to the first intermediate speed ratio provided by gear 170. To wit, the control system simultaneously ports chamber 140 to return to disconnect gear 86 from shaft 20, ports pressurized oil to chamber 96 to momentarily engage clutch 82 and connect input shaft 16 directly to output shaft 20 for bringing gear 170 toward synchronism with shaft 20, and continues to port pressurized oil to charnber 222 of hydraulic actuator 204 while porting chamber 220 of the actuator to return to move rod 214 leftward.
The rate of oil pressure buildup and release in chambers .
96 and 140, respectively, is controlled to c~fect a smooth transition of driving torque from clutch mechanism 84 to clutch mechanism 82. While the driving torque through clutch mechanisms 82 and 84 is incrcas.i.ng and ~ccrea.sing, respectively, the pressuri~.cd oil in chamber 222 acts on distal side 215b of piston 21.5 and IIIOVC5 piston 215, rod 214, spacer 217, and piston 216 leftward toward contact with end wall 210 by piston 216. Initial moveinent of rod 214 is transmitted to f].ange portion 186b of blocker-clutch assembly 30 via coil spring 244 of spring box 206. This initial movement resiliently moves friction clutch member 190 into enyagement with friction clutch member 170a via leaf springs 202 and the chamfered shoulders of split ;
~1 5~982 pins 196. During normal operating conditions, friction clutch members 190 and 170a will engage before clutch mechanism 82 can bring shaft 20 into synchronism with gear 170. ~ence, the reduced diameter portion of pins 188 will move to one side of holes 186c and shoulders 186e and 188c will engage and block engagement of jaw clutch member 186 with jaw clutch member 170a. The blocking action of shoulders 186e and 188c arrests further movement of shift fork 230a and sleeve 230. However, piston rod 214 continues to move leftward until piston 216 contacts end wall 210, thereby compressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186e against blocking shoulders 188c. The blocking action of shoulders 186e and 188c continues until clutch 82 causes gear 170 to cross synchronism with shaft 20. As synchronism is crossed, pins 188 move into axial aligr~ent with holes 186c, thereby allowing the compressed force of spring 244 to quickly move or snap sleeve 230, shift fork 230a, and flange portion 186b leftward and carry jaw clutch member 186 into engagement with jaw clutch member 170a. While the jaw clutch members are engaging, the control system effects an unrestricted porting of chamber 96 to return to quickly disengage clutch mechanism 82. The si~nal to effect a timely portinc3 of chamber 96 t:o return may be provided by an unshown position indicator which senses the leftward movernent of either sleeve 230, fork 230a, flan~e 186b, or jaw clutch member 186. Position indicators of this type are well known in the art.
The blocker-clutch and spring box arran~emen-t enhances the transmission control and operation in sevexal ways. For example, since the force for shifting jaw clutch member 186 is resiliently stored in coil spring 244 of the spring box, control system timing for porting fluid to actuator 2a4 need not be as precise as it would need be if the actuator were moving the jaw clutch member ~S~8;2 directly. Since the force for shifting the jaw clutch member is resiliently stored in the coil spring, the pressure of the oil ported to the actuator need not be precisely controlled. Further, since only sleeve 230 and shift fork 230a move to engage the jaw clutch member when synchronism is reached, the mass of the moving parts is reduced, whereby the jaw clutch member is moved faster with a given force and whereby impulse forces are main-tained relatively low.
When the sensed parameters indicate upshifting from the first intermediate speed ratio, the control system will operate to effect a power upshift from the first intermediate speed ratio provided by gear 170 to the second intermediate speed ratio provided by gear 172.
To effect the power shift out of the first intermediate speed ratio, torque on the splines of jaw cluich members 170a and 186 must be relieved. When the engine is driving the vehicle wheels, the torque (hereinafter called "driving torque") is relieved by momentarily engaging friction clutch 82. However, when the wheels are driving the engine, the torque (hereinafter called "coast mode torque") is merely increased by momentarily actuating friction clutch 82. To relieve the coast mode torque, the control system may be proc3r~lmmed to always momentarily engage friction clutch 84 prior to momentary en~3ac3ement of friction clu-tch 82 or to only momclltarily c~?nc3ac3e friction clutch 84 prior to momelltary enc3a-Jelllent of friction clutch 82 whell the engine power control is less than a predetermined amount, e.g., a 20 percent power position. To effect the shift, the control system simultaneously ports chamber 222 of actuator 240 to return, ports pressurized oil to chamber 218 to apply a rightward force on flange portion 186b via spring 244 of the spring box, momentarily ports pressurized oil to chanber 140 of friction clutch 84 to 3S relieve coast mode torque, and then momentarily ports 115~3Z
pressurized oil to chamber 96 of friction clutch 82 while porting chamber 140 to return. Momentary engagement of clutch 82 relieves any driving torque and allows disengage-ment of jaw clutch member 186 from jaw clutch member 170a and then brings the speed of gear 172 down to synchronism with output shaft 20. While clutches 82 and 84 are re-lieving the torque on ~he splines of the jaw clutch members, the pressurized oil in chamber continues to act on mutually facing side 215a of piston 215, thereby moving rod 214 rightward until piston 215 contacts shoulder 208g. The initial rightward movement of rod 214 compresses coil spring 244 and applies a shifting force which snaps jaw clutch member rightward out of engagement with jaw clutch 170a in response to clutches 82 and 84 relieving the torque on the splines. As flange portion 186b moves rightward, it passes through neutral and the chamfered shoulders of split pins 196 engage the chamfered shoulders of holes 186d, thereby effecting a resilient engagement of friction clutch member 192 with friction clutch member 194 via the force of spring 202.
; During normal operating conditions, friction clutch members 192 and 194 will engage before clutch mechanism 82 can bring shaft 20 into synchronism with gear 172.
Hence, the reduced diameter portion of pins 188 will move to one side of holcs 186c ~nd shoulclers 186f and 188d will engage and block enga~elnent of jaw clutch melllber 186 with jaw clutch member 172a. The blockiny ac~ion of shoulders 186f and 188d arrests further rightward movement of shiEt fork 230a and sleeve 230. }lowever, piston rod 214 is free to continue its riyhtward movement until piston 215 contacts shoulder 208g, thereby compressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186f against blocking shoulders 188d. The blocking action of shoulders 186f and 188d continues until clutch 82 brings gear 172 across synchronism with shaft 20.
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As synchronism is crossed, pins 188 move into axial align-ment with holes 186c, thereby allowing the compressed force of spring 244 to quickly snap jaw clutch member 186 into engagement with jaw clutch member 172a. While the jaw clutch members are engaging, the control system effects an unrestricted porting of chamber 96 to return to quickly disengage clutch mechanism 82. The signal to effect a timely porting of chamber 96 to return may be provided by the unshown position indicator previously mentioned.
When the sensed parameters indicate upshifting from the second intermediate speed ratio~ the control system will operate to effect a power upshift from the second intermediate speed ratio provided by gear 172 to the high or direct drive ratio provided by connecting input shaft 16 directly to output shaft 20 via clutch mechanism 82. To wit, the control system simultaneously ports pressuri~ed oil to chambers 220 and 222 of actuator 204, ports chamber 218 of the actuator to return, momen-tarily ports pressurized oil to chamber 140 to relieve coast mode torque, and then ports pressurized oil to chamber 96 to fully engage clutch mechanism 82 and relieve any driving torque while porting chamber 140 to return.
While clutches 82 and 84 are relieving the torque on the splines of jaw clutch members 186 and 172a, the pressurized oil in chambers 220 and 222 acts on the distal sides of pistons 216 and 215 and moves 216 riyhtward to its neutral position against the stop defined by shoul(ler 208f and Inoves piston 215 leftward to its neutral position acJainst the stop defined hy sleeve 217. Further left~ard movernent of piston 215 and rod 214 is arrested since the area of distal side 216b of piston 216 is greater than the area of distal side 215b of piston 215. The initial leftward movement of rod 214 begins to compress coil spring 244 of spring box 206 and thereby applies an increasing shifting force to flange 186b for snapping jaw clutch memher 186 ~5~32 leftward out of engagement with jaw clutch member 172a when the torque on the splines of jaw clutch members 186 and 172a is relieved by clutches 82 and 84.
Assuming now that the sensed parameters indicate downshifting from the high speed ratio, the control will operate to effect a power downshift from the high speed ratio provided by friction clutch 82 to the second intermediate speed ratio provided by gear 172. To wit, the control system simultaneously ports chamber 96 of clutch 82 to returnf ports pressurized oil to chamber 140 of clutch 86 to momentarily connect output shaft 20 to the countershaft via the low speed ratio gear to bring gear 172 up toward synchronism with output shaft 20, ports pressurized oil to chamber 218 of hydraulic actuator 204, and ports chamber 222 of the actuator to return.
As described with respect to upshifting, the rate of oil flow to and from chambers 140 and 96, respectively, is controlled to effect a smooth transition of driving torque from clutch mechanism 82 to clutch mechanism 84.
While the driving torque through clutch mechanisms 84 and 82 is increasing and decreasing, respectively, the pressurized oil in chamber 218 acts on mutually facing side 215a of piston 215 and moves piston 215 and rod 214 rightward toward contact with shouldex 208g. Initial movement of rod 214 is transmitted to flancJe portion 186b of blocker-clutch assembly 30 via coil spring 24~ of spring box 206. This initial movement resiliently moves friction clutch mcmber 192 into engagement with friction clutch member 194 via leaf spring 202 and the chamfered shoulders of split pins 196. During normal operating conditions, friction clutch membexs 192 and 194 will engage before clutch mechanism 84 can bring gear 172 up to synchronism with shaft 20. Hence, the reduced diameter portion of pins 188 will move to one side of holes 186c and shoulders 186f and 188d will engage and block engagement ~S~32 -20~
of jaw cluteh member 186 with jaw cluteh member 172a.
The blocking action of shoulders 186f and 188d arrests ~urther movement of shift fork 230a and sleeve 230.
However, piston rod 214 continues to move rightward until piston 215 contacts shoulder 208g, thereby com-pressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186f against bloeking shoulders 188d. The blocking action of shoulders 186f ana 188d continues until clutch 84 causes gear 172 to cross synchronism with shaft 20. As synchronism is crossed, pins 188 move into axial alignment with holes 186e, thereby allowing the compressed force of spring 244 to quickly snap jaw clutch member 186 leftward into engage-ment with jaw clutch member 172a. While the jaw clutch members are engaging, the eontrol system ef~ects an unrestricted porting of chamber 140 to return to quickly disengage eluteh mechanism 84. The signal to effect the timely porting oE chamber 140 to return may be provided by the unshown position indicator previously mentioned during the upshifting deseription.
When the sensed parameters indicate downshifting from the second inter:mediate speed ratio, the eontrol system will operate to effect a power downshift from the seeond intennedia-te speed ratio provided by cjear 172 to the first inte;rmediate speed ratio provicled by c3ear 170.
As in upshifting, driving and coast mode torque on the splines must be relievc~d. 'rO ef~ect the shift and relieve the torque, the control system continues to port pressurized oil to chamber 220 of actuator 204, ports chamber 222 of the actuator to return, momentarily ports pressurized oil to chamber 96 to relieve driving torque on the splines of jaw elutch members 186 and 172a, and then momentarily ports pressurized oil to chamber 140 of friction clutch 84 (while porting ehamber 96 to xeturn) to relieve any coast mode torque and to bring the speed 3L15~9~Z
of gear 170 up to synchronism with output shaft 20 after jaw clutch member 186 disengages from jaw clutch member 172a. Further operation to complete the shift is analogous to the operation previously described.
When the sensed parameters indicate downshifting from the first intermediate speed ratio, the control system will operate to effect a power downshift from the first intermediate speed ratio provided by gear 170 to the low speed ratio provided by fully engaging friction clutch 84. To effect the shift and relieve the torque on the splines of jaw clutch member 186 and 170a, the control system ports pressurized oil to chamber 222 of actuator 204, ports chamber 220 to return, momentarily ports pressurized oil to chamber 96 to relieve driving torque on the splines, and then ports pressurized oil to chamber 140 to fully engage friction clutch 84 (while porting char~er 96 to return) to relieve any coast mode torque. Further operation to complete the shift is analogous to the operation previously described.
DESCRIPTION _F FIGURE 6 Looking now at FIGURE 6, therein is shown an alter-native embodiment of the transmission torque converter and input shaft which provides tlle transmission with an automati.c torque converter bypass when the transmission is in the direct or the fou1th spced clrive ratio. In describ-ing the embo~ n-ent of l;~VRE 6, clemenls therein which arc ident:ical to el(!ments in FIGUR~S 1-5 will have the same reference nllmc?rals but sufEixed with a prilne. The alter-native elllbodiment includes a torque converter assembly 300 disposed in bell housing portion 38a', a sleeve shaft or torque converter driven shaft 302 rotatably supported in front housing member 38' by bearing 44', and a bypass shaft 304 rotatably supported within sleeve shaft 302.
The torque converter assembly 300 includes an impeller 306 driven by a shroud 308, a turbine 310 Z
hydraulically driven by the impeller and in turn drivingly ixed to sleeve shaft 302 at 312, and a runner o~ stator 314 which becomes grounded to housing member 38' via a one-way roller clutch 316 carried by a sleeve 318 fixed to the housing member. The rear side of shroud 308 is fixed to a sleeve 320 which rotatably supports the rear of the shroud and drives a pump 322. Pump 322 may be a well known crescent gear pump for pressurizing the torque converter, for lubricating the transmission, and for `- 10 providing pressurized oil to engage friction clutches and actuators in the transmission. The front side of shroud 308 includes a cup-shaped portion 308a having internal splines 308b.
Torque converter driven shaft 302 is integrally formed with a gear 302a analogous to ~ear 16a and in constant mesh with countershaEt gear 78', whereby counter-shaft assembly is driven by the tor~ue converter as in FIGURES 1-5. Bypass shaft 304 is drivingly connected to shroud 308 via splines 308b and is integrally formed with an annular flange portion 304a having external splines 30~b analogous to splines 16d for driving the friction disks of the dlrect drive clutch mech~ ism~ an~ a r~cess 304c carrying bearing 80' for rotatably supporting the front end of the output shaEt, not shown in FIGURE 6. ITence, engagement of clutch mechanism 82' automatically bypasses the torque convcI-~er wit-h its inherent inefficiency and negates t:he need for a separ,lt:c torq~e converter bypass clutch which wonld add to the si~.e and weicjht arId coInpJexity of the transmission and its control system.
The preferred ernbocliments of the invention have been disclosed for illust:rative purposes. Many variations and modifications of the preferred embodiment are believed to be within the spirit of the invention. For example, the blocker-clutch assembly 30 may be replaced with blocker-35 clutch assemblies such as disclosed in U.S. Patents Re 29,601;
3,910,131; and 3,983,979. Also, the power downshift arran~e-ment may be dispensed with in favor of driver manipulation of engine speed to relieve torque on the splines of the jaw clutch members and provide synchronism therebetween. The following claims are intended to cover the inventive portions of the preferred embodiment and variations and modifications within the spirit of the invention.
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This is a division of copending Canadian Patent A~pli-cation Serial No. 340,580, filed November 26, 1979.
This application is relat~l to copending Canadian ~pplications Serial Numbers 340,581, filed November 26, 1979; 340,582, filed November 26, 1979; 340,583, filed November 26, 1979;
and 340,5~5, filed ~ovember 26, 1979. All of these applications are assigned to the assignee of this application.
It i.s known in the art to selectively enc~age and disen-gage positive or ~aw type clutches to shift a transmission from one speed ratio to another. Positive clutches are pre-ferred in transmissions since they are compact and inexpensive :relative to friction clutches and a~e extremely reliable if they are synchronously engaged. Most of these transmissions are manually shiftedcmd employ a manually operated friction eluteh for d:iseonneeting the trallsmissioll input sha:Et Lrom a prime mover when shiEting from OllC' ratio to anot}ler. ",uch dis-conneetincl by the frieti.on elutc~ll })as the d.isadvalltac,le of inter-upting the driving conrlecL:i.on betwoen the prinle mover and the load conrle(-ted to t,he t~l-al-lsmission out:.l)ut sllat-. I~urther, whcn sueh transmissions are used in relati.vely hcavy vell:i.el,es, the vehi,ele op~rator must per:Eorm a double clutchincl manipulation of the friction clutch when shifting from one ratio to ano-ther.
When double elutehing, the operator must momentarily disengage the frietion eluteh to relieve torque on the positive eluteh .' to be disengaged, then momentarily reengage the frietion , ~
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clutch to synchronize the positive clutch to be engaged, asld then momentarily disengage the friction clutch prior to ensagement of the positive clutch to minimize shock loading. Further, when the friction clutch is momentarily ~eengaged, the vehicle operator must either increase or decrease the prime mover speed to bring the positive clutch to synchronism. If the operator is unskilled or if the vehicle is moving slowly and/ox if the vehicle is on a steep grade, it is not uncommon for a shift to be missed or for the positive clutches to be abused due to asynchronous engagement.
Many attempts have been made to adapt the above type of transmissions to automatic or semiautomatic controls to negate the above problems. One such attempt, as disclosed in U.S. Patent 3,589,4g3, proposes positive clutches for engaging the several speed ratios, a first friction clutch for connecting the several speed ratio gears to a prime mover, a second friction clutch for connecting the transmission output sha~t directly to the prime mover and synchronizing the positive clutches during upshifting, and a semiautomatic control system for controlling the sequential operation of the friction and positive clutches when a shift control lever is rnoved from one ratio position to another. When the lever is moved in an upshift sense, thc control automatically provides power upshifting and synchroni~ing by momentarily or partially disengaging the first ~riction clutch and by momentarily or par-tially engaging the sccond friction clutch.
When the lever is moved in a downshift sense, the control automatically provides a partial power downshifting by manipulating engagement and disengagement of the friction clutches, but synchronizing must be provided by engine speed manipulation. During both upshifting and downshiftir.g, the clutch teeth of the positive clutch to be engaged are moved into abutment with each other prior to synchronism therebetween, thereby exposing the positive clutches to asynchronous engagement.
:
According to the present invention there is provided a powershift transmission which has a housing, input drive means, an output drive shaft, and at least one countershaft mounted for rotation in the housing, the countershaft being in constant driving relation with the input drive means. Low and intermediate speed ratio means are provided, each ratio means including a gear pair in constant mesh, one gear of each pair being permanently fixed to one of the shafts and the other gear of each pair being rotatably mounted on the other shaft.
A jaw clutch means is operative when engaged to connect the rotatably mounted intermediate speed ratio gear to the other ~ shaft. A first friction clu-tch is operative when engaged to connect the rotatably mounted low speed ratio qear to the other shaft independent of the intermediate speed ratio gear pair and the jaw clutch. A second friction clutch is operative when engaged to interconnect the input drive me~ans ~Ji th the output shaft for providing a high speed ratlo independent of the other speed ratio means and the otl-er clutches.
~ccordinq to a spc~cific cml)odiment o~ the invention there is provi(led a trallsmission which ;nclnclcs an input shaft and an output shaf-t alld at lcast one co~ crs~aft and ratio change means operative to provide at least lcw, intermediate, and high speed ratio chall~es betwec?n the input and output shafts via the countershaft; the ratio chanc3e means inc]udes a low and an intermediate speed ratio gear mounted for rotation about one of the shafts, first and second jaw clutch members operative when engaged to couple the intermediate gear to the one shaft and to provide the intermediate speed ratio, a first friction clutch fully engageable to couple the low gear to the one shaft and to provide the low speed ratio cg/~
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and momentarily engageable during downshifting into the inter-mediate speed ratio to synchronize the jaw clutch members, and a second friction clutch fully engageable to couple the input shaft directly to the output shaft to provide the high speed ratio and momentarily engageable during upshifting into the intermediate speed ratio to synchroni~e the jaw clutch members.
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BRIEF DESCRIPTION OF_THE DRAWINGS
The transmission of the instant invention is shown in the accompanying drawings in which:
FIGURE 1 i5 a partially sectioned view of the transmission, looking along line 1-1 of FIGURE 2;
FIGURE 2 is an end view of the rear housing member of the transmission;
FIGURE 3 is a partially sectioned view of a torque converter shown in FIGURE l;
FIGURE 4 is a fully sectioned view of a portion of the transmission ratio gearing, clutches, and an actuator-, FIGURES 4A and 4B are detailed views of a portion of a blocker-clutch in FIGURE 4;
FIGURE 5 is a fully sectioned view of another portion of the transmission ratio gearing, clutches, and an actuator; and FIGURE 6 is an alternative embodiment of the transmission torque converter and input shaft.
DETAILED DESCRIP'rION OF THE DRAWINGS
__ _ ~ _ ___ Looking now at FIGURES 1 and 2 and in particular FIGURE 1, therein is shown a powershift transmission 10, partially sectioned along line 1-1 of FIGURE 2. The transmission is intended for use in a land vehicle but is not limited to such use. The transmission is preferably automatically shited by an unshown control system which forms no part of the instant invention. The transmission includes a housing assembly 12, a fluid coupling or torque converter assembly 14 which may be directly driven by an unshown internal combustion engine, an input shaft 16, an output shaft assembly 18 including an output shaft 20, at least one countershaft assembly 22 including countershaft members 24 and 26 splined together at 27, a friction clutch assembly 2 8, a blocker-clutch assembly 30, an actuator assembly 32, and a reverse gear assem~ly 34 including an idler shaft 36.
1~5~182 In describing transmission 10, its leftward portion, as shown in FIGURE 1, will be referred to as the front and its rightward portion will be referred to as the rear.
Ilousing assembly 12 includes a front housing member 38, having a bell housing portion 38a integrally formed therewith, a rear housing member 40, and an intermediate plate member 42. Members 38, 40, and 42 are secured together via a plurality of bolts 43. A flange portion 38b of bell housing 38a provides means for securing the transmission to the rear of an unshown engine. The front housing member carries bearings 44 and 46 for rotatably supporting input shaft 16 and countershaft 24. The rear housing member carries bearings 48, 50, and 52 for rotatably supportiny output shaft 20, countershaft 26, and idler shaft 36.
Looking at both FIGURES 1 and 2, the true position of countershaft 26, idler sh~ft 36, and actuator assembly 30, relative to output shaft 20, may be gleaned from the position of bosses 40a and 40b which carry bearings 50 and 52 and from a boss 40c which defines a portion of a cylinder housing 54 of the actuator assembly 32. Inter-mediate plate 42 includes a through bore 42a for the passage of output shaft 20 and through bores 42b and 42c which carry bearings 56 and 58 for rotatably supporting countershaft 26 and idler shaEt 36. Rear housing me~er 40 further includes a power takeoff pad 40d and a flange 40e for the attachmellt o~ an oil pan 60, shown only in FIGURE 2.
Looking now at FIGURES 1 and 3 and in particular FIGURE 3, torque converter assembly 14 includes an impeller 62 driven by a shroud 64, a turbine 65 hydraulically driven by the impeller and in turn drivingly fixed to input shaft 16 at 66, and a runner or stator 68 which becomes grounded to housing member 38 via a one-way roller clutch 70 carried by a sleeve 72 fixed to the housing member. The rear side of shroud 64 is fixed to ~5~9~32 a sleeve 74 which rotatably supports the rear of the shroud and drives a pump 76. Pump 76 may be a well known crescent gear pump for pressurizing the torque converter, for lubricating the transmission, and for providing pressurized fluid to engage friction clutches and actuators in the transmission.
Looking now at FIGURES 1 and 4 and in particular FIGURE 4, input shaft 16 is integrally formed with an input gear 16a which is in constant mesh with a countershaft gear 78, an annular flange 16b for connecting the input shaft to friction clutch assembly 28, and a recess 16c carrying a bearing 80 for rotatably supporting the front end of output shaft 20. Friction clutch assembly 28 includes a clutch mechanism 82 for connecting the input shaft directly to the output shaft and a clutch mechanism 84 for connecting a low or first speed ratio gear 86, driven by the countershaft, to the output shaft.
Clutch mechanism 82 includes a housing member 88 splined to shaft 20, a set of friction disks 90 slideably splined to internal splines 88a defined by member 88, a set of friction disks 92 slideably splined to external splines 16d defined by annular flange 16b, a piston 94 for squeezing the dis~s together in response to pressurized fluid being introduced into a chamber 96 de~ined by ; 25 housing member 88 and piston 94, and a set of return springs 98 for r~tracting the piston. ~lousing member 8 is axially retained by a shoulder 20a de~ined by a step in shaft 20 and a snap ring 100 which also r~tains a radially extending flange 192 having springs 98 reacting thereagainst. Pressurized oil for actuating clutch 82 is introduced into chamber 96 via a passage 104 in housing 88, passages 106, 108, and 110 in shaft 20, and passages 112 and 114 in intermediate plate 42 and in an annular rim portion 42d which extends the axial interface of bore 42a with shaft 20. Passage 114 is connected to Z
--7~
an unshown control system which is selectively operative to provide the pressurized oil. Passages 108 and 114 are sealed at their for~Yard and rearward ends, respectively, by interference fit balls 116 and 118. Passages 109 and 106 are sealed at their respective interface with member 88 and bore 42a via pairs of seals 105 and 107. Oil for lubricating bearing 80 and the disks of clutch 82 flows through a passage 120 in intermediate plate 42, passages 122, 124, and 126 in shaft 20, and a plurality of ` 10 passages 128 in flange 16b. Passage 124 is sealed at its forward end by an interference fit ball 127.
Clutch mechanism 84 includes a housing member 130 rotatably supported on shaft 20 via a bearing 132, a set of friction disks 134 slideably splined to internal splines 130a defined by member 130, a set of disks 136 slideably splined to external splines 88b defined by housing member 88, a piston 138 for squeezing the disks together in response to pressurized oil being introduced into a cha~ber 140 defined by housing member 130 and piston 138, a set of return springs 142 for retracting the piston, and a hub portion 130b defined by housing member 130. Low ratio gear 86 is splined to hub portion 130b and axially retained thereon by a snap ring 141. Housing member 130 is axially retained ~or rotation relative to housing member 88 and rim portion 42d via thrust bearings 144 and 146. Sprillgs 142 react against a radially exterldincJ
flange 148 secured to member 130 via a snap ring 150.
Pressurir~ed oil for actuating clutch 84 is introduced into chamber 140 via passages 152 and 154 in hub portion 130b and passages lS6 and 158 in rim portion 42d and intermediate plate 42. Passage 156 is sealed at its interface with hub portion 130b via a pair of seals 160.
Passage 158 is sealed at its rear~Yard end by an inter-ference fit ball 162. Oil for lubricating bearings 132, 144, and 146 and the disks of clutch mechanism 84 flows '' , ~15~g8~
through passages 124, 164, and 166. Passage 158 is connected to the unshown control system which is selectively operative to provide the pressurized oil.
Looking now in the area of blocker-clutch mechanism 30, therein are three gears, a reverse speed ratio gear 168 splined to shaft 20 and retained against forward movement by a shoulder 20b and first and second inter-mediate speed ratio gears 170 and 172 supported for rotation on shaft 20 by sleeve bearings 174 and 176. Gears 170 and 172 each include an axially extending sleeve portion or jaw clutch member 170a and 172a which each have external jaw clutch splines 170b and 172b. Gears 170 and 172 are axially spaced apart by a sleeve 178 splined on its I.D. to shaft 20 and retained against axial movement by a shoulder 20c and a snap ring 180. Gears 170 and 172 are ~xially retained on their forward and rearward sides, respectively, by thrust bearings 182 and 184.
Blocker-clutch mechanism 30 includes the jaw clutch members 170a and 172a, a jaw clutch member or means 186 having internal jaw clutch splines 186a slideably splined to external splines on sleeve 178, a radially extending flange portion 186b integrally formed wi-th member 186, three circumferentially positioned pins 188 (one of which is shown) extending parallel to the axis of shaft 20 and through holes 186c in flange portion 18Gb, two friction cone-clutch members 190 and 192 rigidly secured tocJether by pins 188, two friction cc~ne-clutch members 170c and 194 engageable with friction members 190 and 192 and each fixed for rotation with its respective gear, and three circumferentially positioned split pins 196(one of which is shown) alternately spaced between pins 188 and extending parallel to the shaft 20 and through chamfered holes 186d in flange portion 186b.
Looking momentarily at both PIGURES 4 and 4A, each split pin includes a pair of semicylindrical halves 198 ~L~S~82 _9_ and 200 having a major diameter less than the I.~. of holes 186d when squeezed together, semiannular grooves 198a and 200a with ch~nfered ends, and a leaf spring 202 for biasing the annular grooves apart to engage the groove ch~nfers with the hole chamfers. Halves 198 and 200 abut at their ends against end walls l90a and 192a of blind bores in friction members 190 and 192.
Looking momentarily at both FIGURES 4 and 4B, each hole 186c extends parallel to the axis of shaft 20 and includes oppositely facing square shoulders 186e and 186f positioned normal to the axis of shaft 20. Each pin 188 includes a major diameter 188a less than the I.D. of its respective hole 186c and a groove or reduced diameter portion 188b defining oppositely facing blocking shoulders 188c and 188d which are parallel to square shoulders 186e and 186f.
When blocker-clutch mechanism 30 is in the disengaged or neutral position, as shown, gears 170 and 172 are free to rotate relative to shaft 20. When it is desired to couple either gear to the shaft, actuator assembly 32 applies an actuating or engaging force to flange portion 186b to effect movement of jaw clutch member :l86 toward the jaw clutch members 170a or 172a. If the engaging force is to the left, initial movement of the flange portion is transmitted through split pins 196 via leaf spring 202 and the chamfered sho~lders to e~ffcct resilient engagement of friction members 190 and 170a. This resilient engagement (provided gcar 170 and shaft 20 are rotating asynchronously) causes the reduced diame-ter portion 188b of pins 188 to move to one side of holes 186c, whereby square shoulders 186e engage blocking shoulders 188c to block engagement of jaw clutch member 186 with jaw clutch member 170a until gear 170 crosses synchronism with shaft 20. Since shoulders 186e and 188c are normal to the axis of shaft 20 and the direction of movement of ~5~9B2 jaw clutch member 186~ the shoulders provide a positive or infinite block which is independent of the forces on the shoulders and the frictional torque between friction clutch members 190 and 170c, ther~by preventing asynchronous engagement of the jaw clutch members should the design frictional torque between the friction members be slow in developing due to oil on the friction surfaces or should the design frictional torque fade due to a change in the coefficient friction of the surfaces.
Actuator assembly 32 includes a hydraulic actuator 204 and a spring box 206. Actuator 204 includes the cylinder housing 54 defined by rear housing member 40, cylindrical bore portions 208a, 208b, 208c, and 208d de-fined by a stepped bore 208 having shoulders 208e, 208f, and 208g, an end wall 210 abutting shoulder 208e and retained thereagainst by à snap ring 212, a piston rod 214 disposed in bore 208 for sliding movement parallel to the axis of shaft 20 and radially spaced therefrom, a piston 215 integrally formed with the piston rod for sliding rnovement in bore portion 208c, a piston 216 disposed for sliding movement within bore portion 208b and on piston rod 21~, and a sleeve or stop member 217 slideably supported by piston rod 214 and interposed between the pistons. Piston rod 214 includes an end portion 214a slideably disposed in bore portion 208d for support purposes and an cnd portion 214b cxtcn~l;ng through end wall 210. Pistons 215 and 216 divide hore portions 208b and 208c into three fluid chambers. The mutually facing sides 215a and 216a oE the pistons in part define a first fluid chamber 218 and the distal sides 215b and 216b of the pistons in part define second and third fluid chambers 220 and 222. Passages 224, 226, and 228 provide means for porting oil to and from the fluid chambers via the unshown control system. Conventional seals prevent oil leakage of the cylinder and by the pistons. The seals 1 3LS~8Z
.
may be Quad-X Brand Seals obtainable fro~ Minnesota Rubber Company.
Spring box 206 includes a sleeve 230 concentric to end portion 214b of the piston rod 214, annular bearing rings 232 and 234 slideably supporting the sleeve on the end portion, snap rings ~36, 238, 240 and 242 defin-ing stop means, a pre-loaded coil spring 244 interposed between the bearing rings and ~iasing the rings apart - and into engagement with the stop means defined by the snap rings, and a shift fork 230a integrally formed with the sleeve. Shift fork 230a extends outward around the periphery of flange portion 186b and connects the flange portion to the sleeve in a conventional manner, as may be seen in FIGURE 1. searing rings 232 and 234 are spaced apart as far as practicable to minimize shift fork cocking forces between the sleeve and end portion. Further, each ring includes concentric sleeve portions, such as sleeves 232a and 232b, which define an annular recess for receiving the spring ends and for increasing -the outer and inner circumferential bearing surface of the rings, thereby lowering the surface forces on the bearings to reduce wear.
Looking now at FIGURES 1 and 5 and in particular FIGURE 5, countershaft assembly 22 incl-lcles the counter-shaft mem~ers 24 and 26, the gear 78 fixed for rotationwith shaft 24 and in conskant mcsh with ;n~ut cJear 16a, the splined connection 27 connccL-iny shaft 24 to shaft 26, gears 246, 248, and 250 fixed for rotation with shaft 26 and in constant mesh with gears 86, 170, and 172, respectively, and a power take-off gear 252 also fixed for rotation with shaft 26.
Reverse gear assembly 34 includes the idler shaft 36, a gear 254 supported for rotation about shaft 36 via a sleeve ~earing 256 and in constant mesh with gear 248, a gear 258 fixed for rotation with shaft 36 and in constant 3 15~8:~
mesh with the reverse speed ratio gear 168 when shaft 36 is in its true position as described in connection with housing assembly 12 and FIGUP~ 2, a positive clutch assembly 260 for coupling gear 254 with shaft 36, and a hydraulic actuator 262 for selectlvely moving the clutch into and out of engagement.
Positive clutch 260 includes a set of jaw clutch teeth 254a defined by gear 25~, a jaw clutch member 264 slideably splined to shaft 36, a set of jaw clutch teeth 264a defined by member 264 and engageable with teeth 254a, and an annular groove 264b which receives a shift fork 266.
~ ydraulic actuator 262 includes a piston 268a formed with or fixed to a rod 268 and disposed in a cylinder defined by rear housing member 40, an end plate 269 for closing the cylinder, and the shift fork 2~6 fixed to rod 268. Hydraulic sealing of the piston and cylinder is provided by seals in a conventional manner.
Passages 270 and 272 provide means for porting oil to and from the actuator via the unshown control system.
OPERATION
In reviewing the operation, it wlll be assumed that transmission 10 is installed in a land vehicle having an internal combustion engine coupled di~ectly to shroud 64 of the torque converter, and that a shift control system will automatically effcct shifting t:o l:hc dcsired speed ratios in the proper sequence. Such control systems are well known and are often made responsive to parameters such as engine load and vehicle speed. It will also be assumed that the shift control system includes a shift contro] selector which is selectively placed in a neutral position to disengage the transmission, in a drive position to effect forward movement of the vehicle, and in a reverse position to effect reverse movement of the ~15~32 vehicle. However, the shift control selector could have four forward drive positions corresponding to the four forward speed ratios of the transmission- in which case, the shift control system could be made operative to engage only the ratio corresponding to the selector position or sequentially upshift and downshift between the low speed ratio and the highest ratio corresponding to the position of the selector. The shift control systems referred to ~erein are by way of example only and do not form part of the invention herein nor are they purported to be preferred forms of shift control systems.
In the following operational description, friction clutch 82 and 84 will be referred to as being either fully engaged or momentarily engaged. When fully engaged, the clutch locks-up. When momentarily engaged, the clutch slips. To implement the slipping, the control system pressure for engaging the clutch may be reduced and/or supplied for such a short period that full engagement or lock-up is not reached.
With the shift control lever in neutral and the engine running, input shaft 16 is driven by torque converter assembly 14; countershafts 24 and 26 are driven at a speed proportional to tlle speed of input shaft 16 via gears 16a and 78; ratio gears 86, 170, and 72 are driven at speeds proportional to their respective counter-shaft gears 246, 248 and 250; and the co~trol system ports pressuri~ed oil to cllambers 220 and 222 of hydraulic actuator 204 to position rod 214 in the nc~ltral position as shown in the drawings. Further, output shaft 20 is completely disconnected from input shaft 16 and counter-shafts 24 and 26 since friction clutches 82 and 84, blocker-clutch assembly 30, and positive clu~ch 260 are all di5engaged.
Assume now that a vehicle operator places the shift control lever in the drive position and wishes to accelerate ~ IL5~
the vehicle in a forward direction to a speed which will cause the control system to sequentially power upshift through each of the four ~orward drive ratios of the transmission. When the shift lever is placed in drive, the control system fully engages friction clutch 84 by porting pressurized oil to chamber 140 thereby squeezing friction disks 134 and 136 together and connecting gear 86 to output shaft 20 via housings 130 and 88 of clutches 84 and 82, respectively.
When the sensed parameters indicate upshifting from the low speed ratio, the control system will operate to effect a power upshift from the low speed ratio provided by gear 86 to the first intermediate speed ratio provided by gear 170. To wit, the control system simultaneously ports chamber 140 to return to disconnect gear 86 from shaft 20, ports pressurized oil to chamber 96 to momentarily engage clutch 82 and connect input shaft 16 directly to output shaft 20 for bringing gear 170 toward synchronism with shaft 20, and continues to port pressurized oil to charnber 222 of hydraulic actuator 204 while porting chamber 220 of the actuator to return to move rod 214 leftward.
The rate of oil pressure buildup and release in chambers .
96 and 140, respectively, is controlled to c~fect a smooth transition of driving torque from clutch mechanism 84 to clutch mechanism 82. While the driving torque through clutch mechanisms 82 and 84 is incrcas.i.ng and ~ccrea.sing, respectively, the pressuri~.cd oil in chamber 222 acts on distal side 215b of piston 21.5 and IIIOVC5 piston 215, rod 214, spacer 217, and piston 216 leftward toward contact with end wall 210 by piston 216. Initial moveinent of rod 214 is transmitted to f].ange portion 186b of blocker-clutch assembly 30 via coil spring 244 of spring box 206. This initial movement resiliently moves friction clutch member 190 into enyagement with friction clutch member 170a via leaf springs 202 and the chamfered shoulders of split ;
~1 5~982 pins 196. During normal operating conditions, friction clutch members 190 and 170a will engage before clutch mechanism 82 can bring shaft 20 into synchronism with gear 170. ~ence, the reduced diameter portion of pins 188 will move to one side of holes 186c and shoulders 186e and 188c will engage and block engagement of jaw clutch member 186 with jaw clutch member 170a. The blocking action of shoulders 186e and 188c arrests further movement of shift fork 230a and sleeve 230. However, piston rod 214 continues to move leftward until piston 216 contacts end wall 210, thereby compressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186e against blocking shoulders 188c. The blocking action of shoulders 186e and 188c continues until clutch 82 causes gear 170 to cross synchronism with shaft 20. As synchronism is crossed, pins 188 move into axial aligr~ent with holes 186c, thereby allowing the compressed force of spring 244 to quickly move or snap sleeve 230, shift fork 230a, and flange portion 186b leftward and carry jaw clutch member 186 into engagement with jaw clutch member 170a. While the jaw clutch members are engaging, the control system effects an unrestricted porting of chamber 96 to return to quickly disengage clutch mechanism 82. The si~nal to effect a timely portinc3 of chamber 96 t:o return may be provided by an unshown position indicator which senses the leftward movernent of either sleeve 230, fork 230a, flan~e 186b, or jaw clutch member 186. Position indicators of this type are well known in the art.
The blocker-clutch and spring box arran~emen-t enhances the transmission control and operation in sevexal ways. For example, since the force for shifting jaw clutch member 186 is resiliently stored in coil spring 244 of the spring box, control system timing for porting fluid to actuator 2a4 need not be as precise as it would need be if the actuator were moving the jaw clutch member ~S~8;2 directly. Since the force for shifting the jaw clutch member is resiliently stored in the coil spring, the pressure of the oil ported to the actuator need not be precisely controlled. Further, since only sleeve 230 and shift fork 230a move to engage the jaw clutch member when synchronism is reached, the mass of the moving parts is reduced, whereby the jaw clutch member is moved faster with a given force and whereby impulse forces are main-tained relatively low.
When the sensed parameters indicate upshifting from the first intermediate speed ratio, the control system will operate to effect a power upshift from the first intermediate speed ratio provided by gear 170 to the second intermediate speed ratio provided by gear 172.
To effect the power shift out of the first intermediate speed ratio, torque on the splines of jaw cluich members 170a and 186 must be relieved. When the engine is driving the vehicle wheels, the torque (hereinafter called "driving torque") is relieved by momentarily engaging friction clutch 82. However, when the wheels are driving the engine, the torque (hereinafter called "coast mode torque") is merely increased by momentarily actuating friction clutch 82. To relieve the coast mode torque, the control system may be proc3r~lmmed to always momentarily engage friction clutch 84 prior to momentary en~3ac3ement of friction clu-tch 82 or to only momclltarily c~?nc3ac3e friction clutch 84 prior to momelltary enc3a-Jelllent of friction clutch 82 whell the engine power control is less than a predetermined amount, e.g., a 20 percent power position. To effect the shift, the control system simultaneously ports chamber 222 of actuator 240 to return, ports pressurized oil to chamber 218 to apply a rightward force on flange portion 186b via spring 244 of the spring box, momentarily ports pressurized oil to chanber 140 of friction clutch 84 to 3S relieve coast mode torque, and then momentarily ports 115~3Z
pressurized oil to chamber 96 of friction clutch 82 while porting chamber 140 to return. Momentary engagement of clutch 82 relieves any driving torque and allows disengage-ment of jaw clutch member 186 from jaw clutch member 170a and then brings the speed of gear 172 down to synchronism with output shaft 20. While clutches 82 and 84 are re-lieving the torque on ~he splines of the jaw clutch members, the pressurized oil in chamber continues to act on mutually facing side 215a of piston 215, thereby moving rod 214 rightward until piston 215 contacts shoulder 208g. The initial rightward movement of rod 214 compresses coil spring 244 and applies a shifting force which snaps jaw clutch member rightward out of engagement with jaw clutch 170a in response to clutches 82 and 84 relieving the torque on the splines. As flange portion 186b moves rightward, it passes through neutral and the chamfered shoulders of split pins 196 engage the chamfered shoulders of holes 186d, thereby effecting a resilient engagement of friction clutch member 192 with friction clutch member 194 via the force of spring 202.
; During normal operating conditions, friction clutch members 192 and 194 will engage before clutch mechanism 82 can bring shaft 20 into synchronism with gear 172.
Hence, the reduced diameter portion of pins 188 will move to one side of holcs 186c ~nd shoulclers 186f and 188d will engage and block enga~elnent of jaw clutch melllber 186 with jaw clutch member 172a. The blockiny ac~ion of shoulders 186f and 188d arrests further rightward movement of shiEt fork 230a and sleeve 230. }lowever, piston rod 214 is free to continue its riyhtward movement until piston 215 contacts shoulder 208g, thereby compressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186f against blocking shoulders 188d. The blocking action of shoulders 186f and 188d continues until clutch 82 brings gear 172 across synchronism with shaft 20.
LS~g~Z
As synchronism is crossed, pins 188 move into axial align-ment with holes 186c, thereby allowing the compressed force of spring 244 to quickly snap jaw clutch member 186 into engagement with jaw clutch member 172a. While the jaw clutch members are engaging, the control system effects an unrestricted porting of chamber 96 to return to quickly disengage clutch mechanism 82. The signal to effect a timely porting of chamber 96 to return may be provided by the unshown position indicator previously mentioned.
When the sensed parameters indicate upshifting from the second intermediate speed ratio~ the control system will operate to effect a power upshift from the second intermediate speed ratio provided by gear 172 to the high or direct drive ratio provided by connecting input shaft 16 directly to output shaft 20 via clutch mechanism 82. To wit, the control system simultaneously ports pressuri~ed oil to chambers 220 and 222 of actuator 204, ports chamber 218 of the actuator to return, momen-tarily ports pressurized oil to chamber 140 to relieve coast mode torque, and then ports pressurized oil to chamber 96 to fully engage clutch mechanism 82 and relieve any driving torque while porting chamber 140 to return.
While clutches 82 and 84 are relieving the torque on the splines of jaw clutch members 186 and 172a, the pressurized oil in chambers 220 and 222 acts on the distal sides of pistons 216 and 215 and moves 216 riyhtward to its neutral position against the stop defined by shoul(ler 208f and Inoves piston 215 leftward to its neutral position acJainst the stop defined hy sleeve 217. Further left~ard movernent of piston 215 and rod 214 is arrested since the area of distal side 216b of piston 216 is greater than the area of distal side 215b of piston 215. The initial leftward movement of rod 214 begins to compress coil spring 244 of spring box 206 and thereby applies an increasing shifting force to flange 186b for snapping jaw clutch memher 186 ~5~32 leftward out of engagement with jaw clutch member 172a when the torque on the splines of jaw clutch members 186 and 172a is relieved by clutches 82 and 84.
Assuming now that the sensed parameters indicate downshifting from the high speed ratio, the control will operate to effect a power downshift from the high speed ratio provided by friction clutch 82 to the second intermediate speed ratio provided by gear 172. To wit, the control system simultaneously ports chamber 96 of clutch 82 to returnf ports pressurized oil to chamber 140 of clutch 86 to momentarily connect output shaft 20 to the countershaft via the low speed ratio gear to bring gear 172 up toward synchronism with output shaft 20, ports pressurized oil to chamber 218 of hydraulic actuator 204, and ports chamber 222 of the actuator to return.
As described with respect to upshifting, the rate of oil flow to and from chambers 140 and 96, respectively, is controlled to effect a smooth transition of driving torque from clutch mechanism 82 to clutch mechanism 84.
While the driving torque through clutch mechanisms 84 and 82 is increasing and decreasing, respectively, the pressurized oil in chamber 218 acts on mutually facing side 215a of piston 215 and moves piston 215 and rod 214 rightward toward contact with shouldex 208g. Initial movement of rod 214 is transmitted to flancJe portion 186b of blocker-clutch assembly 30 via coil spring 24~ of spring box 206. This initial movement resiliently moves friction clutch mcmber 192 into engagement with friction clutch member 194 via leaf spring 202 and the chamfered shoulders of split pins 196. During normal operating conditions, friction clutch membexs 192 and 194 will engage before clutch mechanism 84 can bring gear 172 up to synchronism with shaft 20. Hence, the reduced diameter portion of pins 188 will move to one side of holes 186c and shoulders 186f and 188d will engage and block engagement ~S~32 -20~
of jaw cluteh member 186 with jaw cluteh member 172a.
The blocking action of shoulders 186f and 188d arrests ~urther movement of shift fork 230a and sleeve 230.
However, piston rod 214 continues to move rightward until piston 215 contacts shoulder 208g, thereby com-pressing coil spring 244 of spring box 206 and resiliently loading square shoulders 186f against bloeking shoulders 188d. The blocking action of shoulders 186f ana 188d continues until clutch 84 causes gear 172 to cross synchronism with shaft 20. As synchronism is crossed, pins 188 move into axial alignment with holes 186e, thereby allowing the compressed force of spring 244 to quickly snap jaw clutch member 186 leftward into engage-ment with jaw clutch member 172a. While the jaw clutch members are engaging, the eontrol system ef~ects an unrestricted porting of chamber 140 to return to quickly disengage eluteh mechanism 84. The signal to effect the timely porting oE chamber 140 to return may be provided by the unshown position indicator previously mentioned during the upshifting deseription.
When the sensed parameters indicate downshifting from the second inter:mediate speed ratio, the eontrol system will operate to effect a power downshift from the seeond intennedia-te speed ratio provided by cjear 172 to the first inte;rmediate speed ratio provicled by c3ear 170.
As in upshifting, driving and coast mode torque on the splines must be relievc~d. 'rO ef~ect the shift and relieve the torque, the control system continues to port pressurized oil to chamber 220 of actuator 204, ports chamber 222 of the actuator to return, momentarily ports pressurized oil to chamber 96 to relieve driving torque on the splines of jaw elutch members 186 and 172a, and then momentarily ports pressurized oil to chamber 140 of friction clutch 84 (while porting ehamber 96 to xeturn) to relieve any coast mode torque and to bring the speed 3L15~9~Z
of gear 170 up to synchronism with output shaft 20 after jaw clutch member 186 disengages from jaw clutch member 172a. Further operation to complete the shift is analogous to the operation previously described.
When the sensed parameters indicate downshifting from the first intermediate speed ratio, the control system will operate to effect a power downshift from the first intermediate speed ratio provided by gear 170 to the low speed ratio provided by fully engaging friction clutch 84. To effect the shift and relieve the torque on the splines of jaw clutch member 186 and 170a, the control system ports pressurized oil to chamber 222 of actuator 204, ports chamber 220 to return, momentarily ports pressurized oil to chamber 96 to relieve driving torque on the splines, and then ports pressurized oil to chamber 140 to fully engage friction clutch 84 (while porting char~er 96 to return) to relieve any coast mode torque. Further operation to complete the shift is analogous to the operation previously described.
DESCRIPTION _F FIGURE 6 Looking now at FIGURE 6, therein is shown an alter-native embodiment of the transmission torque converter and input shaft which provides tlle transmission with an automati.c torque converter bypass when the transmission is in the direct or the fou1th spced clrive ratio. In describ-ing the embo~ n-ent of l;~VRE 6, clemenls therein which arc ident:ical to el(!ments in FIGUR~S 1-5 will have the same reference nllmc?rals but sufEixed with a prilne. The alter-native elllbodiment includes a torque converter assembly 300 disposed in bell housing portion 38a', a sleeve shaft or torque converter driven shaft 302 rotatably supported in front housing member 38' by bearing 44', and a bypass shaft 304 rotatably supported within sleeve shaft 302.
The torque converter assembly 300 includes an impeller 306 driven by a shroud 308, a turbine 310 Z
hydraulically driven by the impeller and in turn drivingly ixed to sleeve shaft 302 at 312, and a runner o~ stator 314 which becomes grounded to housing member 38' via a one-way roller clutch 316 carried by a sleeve 318 fixed to the housing member. The rear side of shroud 308 is fixed to a sleeve 320 which rotatably supports the rear of the shroud and drives a pump 322. Pump 322 may be a well known crescent gear pump for pressurizing the torque converter, for lubricating the transmission, and for `- 10 providing pressurized oil to engage friction clutches and actuators in the transmission. The front side of shroud 308 includes a cup-shaped portion 308a having internal splines 308b.
Torque converter driven shaft 302 is integrally formed with a gear 302a analogous to ~ear 16a and in constant mesh with countershaEt gear 78', whereby counter-shaft assembly is driven by the tor~ue converter as in FIGURES 1-5. Bypass shaft 304 is drivingly connected to shroud 308 via splines 308b and is integrally formed with an annular flange portion 304a having external splines 30~b analogous to splines 16d for driving the friction disks of the dlrect drive clutch mech~ ism~ an~ a r~cess 304c carrying bearing 80' for rotatably supporting the front end of the output shaEt, not shown in FIGURE 6. ITence, engagement of clutch mechanism 82' automatically bypasses the torque convcI-~er wit-h its inherent inefficiency and negates t:he need for a separ,lt:c torq~e converter bypass clutch which wonld add to the si~.e and weicjht arId coInpJexity of the transmission and its control system.
The preferred ernbocliments of the invention have been disclosed for illust:rative purposes. Many variations and modifications of the preferred embodiment are believed to be within the spirit of the invention. For example, the blocker-clutch assembly 30 may be replaced with blocker-35 clutch assemblies such as disclosed in U.S. Patents Re 29,601;
3,910,131; and 3,983,979. Also, the power downshift arran~e-ment may be dispensed with in favor of driver manipulation of engine speed to relieve torque on the splines of the jaw clutch members and provide synchronism therebetween. The following claims are intended to cover the inventive portions of the preferred embodiment and variations and modifications within the spirit of the invention.
cg/~b :
Claims (8)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. In a powershift transmission of the type including a housing; input drive means, an output shaft, and at least one countershaft mounted for rotation in said housing, said countershaft in constant driving relation with said input drive means; low and intermediate speed ratio means, each ratio means including a gear pair in constant mesh, one gear of each pair permanently fixed to one of said shafts and the other gear of each pair rotatably mounted on said other shaft; the improvement comprising:
jaw clutch means operative when engaged to connect said rotatably mounted intermediate speed ratio gear to said other shaft;
a first friction clutch operative when engaged to connect said rotatably mounted low-speed ratio gear to said other shaft independent of said intermediate speed ratio gear pair and said jaw clutch; and a second friction clutch operative when engaged to interconnect said input drive means with said output shaft for providing a high-speed ratio independent of said other speed ratio means and said other clutches.
jaw clutch means operative when engaged to connect said rotatably mounted intermediate speed ratio gear to said other shaft;
a first friction clutch operative when engaged to connect said rotatably mounted low-speed ratio gear to said other shaft independent of said intermediate speed ratio gear pair and said jaw clutch; and a second friction clutch operative when engaged to interconnect said input drive means with said output shaft for providing a high-speed ratio independent of said other speed ratio means and said other clutches.
2. In a powershift transmission of the type including a housing; input drive means, an output shaft, and at least one countershaft mounted for rotation in said housing, said countershaft in constant driving relation with said input drive means; low, and first and second intermediate speed ratio means, each ratio means including a gear pair in constant mesh, one gear of each pair fixed to one of said shafts and the other gear of each pair rotatably mounted on said other shaft; the improvement comprising:
jaw clutch means disposed between said rotatably mounted first and second intermediate speed ratio gears for selectively connecting said rotatably mounted first and second intermediate ratio gears to said other shaft;
a first friction clutch operative when engaged to connect said rotatably mounted low-speed ratio gear to said other shaft independent of said first and second inter-mediate speed ratio gear pairs and said jaw clutch means; and a second friction clutch operative when engaged to interconnect said input drive means with said output shaft for providing a high-speed ratio independent of said other speed ratio gear pairs and said other clutches.
jaw clutch means disposed between said rotatably mounted first and second intermediate speed ratio gears for selectively connecting said rotatably mounted first and second intermediate ratio gears to said other shaft;
a first friction clutch operative when engaged to connect said rotatably mounted low-speed ratio gear to said other shaft independent of said first and second inter-mediate speed ratio gear pairs and said jaw clutch means; and a second friction clutch operative when engaged to interconnect said input drive means with said output shaft for providing a high-speed ratio independent of said other speed ratio gear pairs and said other clutches.
3. The transmission of Claim 1 or 2 wherein said jaw clutch includes:
blocker means for preventing asynchronous engagement of the jaw clutch means.
blocker means for preventing asynchronous engagement of the jaw clutch means.
4. The transmission of Claim 1 or 2 wherein said input drive means includes:
a fluid coupling having an input directly connectable to a source of power and an output in constant driving relation with said countershaft; and a bypass sahft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
a fluid coupling having an input directly connectable to a source of power and an output in constant driving relation with said countershaft; and a bypass sahft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
5. The transmission of Claim 1, wherein said first friction clutch is momentarily engageable during downshifting into said intermediate speed ratio to synchronize said jaw.
clutch means for engagement, said second friction clutch is momentarily engageable during upshifting into said intermediate speed ratio to synchronize said jaw clutch means for engagement, and further including:
blocker means for preventing asynchronous engagement of said jaw clutch means.
clutch means for engagement, said second friction clutch is momentarily engageable during upshifting into said intermediate speed ratio to synchronize said jaw clutch means for engagement, and further including:
blocker means for preventing asynchronous engagement of said jaw clutch means.
6. The transmission of Claim 5, wherein said input drive means includes:
a fluid coupling having an input directly connectable to a source of power and an output in said constant driving relation with said countershaft; and a bypass shaft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
a fluid coupling having an input directly connectable to a source of power and an output in said constant driving relation with said countershaft; and a bypass shaft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
7. The transmission of Claim 2, wherein said first friction clutch is momentarily engageable during downshifting into said intermediate speed ratio to synchronize said jaw clutch means for engagement, said second friction clutch is momentarily engageable during upshifting into said intermediate speed ratio to synchronize said jaw clutch means for engage-ment, and further including:
blocker means for preventing asynchronous engagement of said jaw clutch means.
blocker means for preventing asynchronous engagement of said jaw clutch means.
8. The transmission of Claim 7, wherein said input drive means includes:
a fluid coupling having an input directly connectable to a source of power and an output in said constant driving relation with said countershaft; and a bypass shaft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
a fluid coupling having an input directly connectable to a source of power and an output in said constant driving relation with said countershaft; and a bypass shaft having an input directly connectable to said source of power and an output connectable to said output shaft via said second friction clutch to provide said high speed ratio.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000389180A CA1150982A (en) | 1978-12-26 | 1981-10-30 | Powershift synchronized transmission |
Applications Claiming Priority (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/973,271 US4329885A (en) | 1978-12-26 | 1978-12-26 | Powershift synchronized transmission |
| US973,271 | 1978-12-26 | ||
| CA340,580A CA1128781A (en) | 1978-12-26 | 1979-11-26 | Powershift synchronized transmission |
| CA000389180A CA1150982A (en) | 1978-12-26 | 1981-10-30 | Powershift synchronized transmission |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150982A true CA1150982A (en) | 1983-08-02 |
Family
ID=27166502
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000389180A Expired CA1150982A (en) | 1978-12-26 | 1981-10-30 | Powershift synchronized transmission |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1150982A (en) |
-
1981
- 1981-10-30 CA CA000389180A patent/CA1150982A/en not_active Expired
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| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |