Abstract:
A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque-transmitting devices. Further, a hydraulic fluid control circuit is provided for controlling the operation of the plurality of torque-transmitting devices. The hydraulic fluid control circuit receives pressurized hydraulic fluid from an off-axis hydraulic fluid pump and has a plurality of fluid passages disposed in the transmission house, input member and other coupling members.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a divisional application of U.S. application Ser. No. 13/361,534 filed on Jan. 30, 2012 which is a continuation application of U.S. patent application Ser. No. 12/434,272 filed on May 1, 2009 and as such, claims priority thereto under 35 U.S.C. §120. 
    
    
     FIELD 
     The present invention relates generally to multiple speed transmissions having a plurality of planetary gear sets and a plurality of torque-transmitting devices and more particularly to a hydraulic control circuit for controlling the operation of the plurality of torque-transmitting devices. 
     BACKGROUND 
     The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
     A typical multiple speed transmission uses a combination of friction clutches, planetary gear arrangements and fixed interconnections to achieve a plurality of gear ratios. The number and physical arrangement of the planetary gear sets, generally, are dictated by packaging, cost and desired speed ratios. 
     While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved control systems is essentially constant. More efficient hydraulic controls require less energy and provide improved performance, weight efficiency and driver satisfaction. Accordingly, there is a need for an improved, cost-effective, compact multiple speed transmission. 
     SUMMARY 
     A transmission is provided having an input member, an output member, four planetary gear sets, a plurality of coupling members and a plurality of torque transmitting devices. Each of the planetary gear sets includes first, second and third members. The torque transmitting devices are for example clutches and brakes. 
     An embodiment of the transmission is provided having a transmission housing having a center support and a front support. The center support includes a first apply fluid passage, a second apply fluid passage, a third apply fluid passage, and a first dam fluid passage. The front support includes a fourth apply fluid passage and a second dam fluid passage. The transmission further includes a first, a second, a third, and a fourth planetary gear sets each having a first, a second, and a third members. The transmission further includes five torque-transmitting mechanisms each having an apply chamber and a piston for selectively interconnecting at least one of the first, second, and third members with at least one other of the first members, second members, third members, and the transmission housing. The first apply fluid passage is in communication with a first apply chamber of the first of the five torque-transmitting mechanisms. The second apply fluid passage is in communication with a second apply chamber of the first of the five torque-transmitting mechanisms. The first dam fluid passage is in communication with the dam chamber of the first of the five torque-transmitting mechanisms. The third apply fluid passage is in communication with the apply chamber of the second of the five torque-transmitting mechanisms. The fourth apply fluid passage is in communication with the apply chamber of the third of the five torque-transmitting mechanisms. The second dam fluid passage is in communication with the dam chamber of the third of the five torque-transmitting mechanisms. The transmission further includes an input member continuously interconnected to the second member of the second planetary gear set. The input member has a first, a second, and a third bore disposed parallel to a longitudinal axis of the input member. The input member further has a first port in communication with the first bore and a second port in communication with the third bore, a first and second dam port in communication with the second bore, a first apply port in communication with the first bore, and a second apply port in communication with the third bore. The transmission further includes an output member continuously interconnected to at least one of the second member of the fourth planetary gear set and the second member of the third planetary gear set. The first member of the fourth planetary gear set has an intermediate bore in communication with the second bore of the input shaft, a first apply side port in communication with the apply chamber of the fourth of the five torque-transmitting mechanisms, a second apply side port in communication with the apply chamber of the fifth of the five torque-transmitting mechanisms, a first dam side port in communication with the dam chamber of the fourth of the five torque-transmitting mechanisms, and a second dam side port in communication with the dam chamber of the fifth of the five torque-transmitting mechanisms and the intermediate bore. The transmission further includes a first interconnecting member continuously interconnecting the first member of the first planetary gear set with the first member of the second planetary gear set, a second interconnecting member continuously interconnecting the second member of the first planetary gear set with the third member of the fourth planetary gear set, a third interconnecting member continuously interconnecting the third member of the second planetary gear set with the first member of the third planetary gear set, and a fourth interconnecting member continuously interconnecting the second member of the third planetary gear set with the second member of the fourth planetary gear set. 
     In another embodiment of the present invention, the first of the five torque-transmitting mechanisms is selectively engageable to interconnect the third member of the first planetary gear set with the stationary element. The second of the five torque-transmitting mechanisms is selectively engageable to interconnect at least one of the first member of the first planetary gear set and the first member of the second planetary gear set with the stationary element. The third of the five torque-transmitting mechanisms is selectively engageable to interconnect at least one of the second member of the second planetary gear set and the input member with the first member of the fourth planetary gear set. The fourth of the five torque-transmitting mechanisms is selectively engageable to interconnect at least one of the third member of the second planetary gear set and the first member of the third planetary gear set with the first member of the fourth planetary gear set. The fifth of the five torque-transmitting mechanisms is selectively engageable to interconnect the third member of the third planetary gear set with the first member of the fourth planetary gear set. The five torque-transmitting mechanisms include a first and second brake and a first, a second, and a third clutch. 
     In yet another embodiment of the present invention, the torque-transmitting mechanisms are selectively engageable in combinations of at least three to establish at least eight forward speed ratios and at least one reverse speed ratio between the input member and the output member. 
     In yet another embodiment of the present invention, the transmission further comprises a sleeve shaft supported by the front support of the transmission housing, a plurality of input member seals, a first annular channel, a second annular channel, and a third annular channel. The annular channels are defined by the inner surface of the sleeve shaft, the outer surface of the input member, and the plurality of input member seals. The first annular channel communicates with the first port, the second annular channel communicates with the second port, and the third annular channel communicates with the first dam port and the second dam fluid passage of the front support. 
     In yet another embodiment of the present invention, the transmission further comprises a plurality of intermediate member seals, a fourth annular channel, a fifth annular channel, and a sixth annular channel. The annular channels are defined by the outer surface of the input member, the inner surface of the intermediate shaft, and the plurality of intermediate member seals. The fourth annular channel communicates with the first apply port and the first apply side port of the intermediate member, the fifth annular channel communicates with the second dam port and the first dam side port of the intermediate member, and the sixth annular channel communicates with the second apply port and the second apply side port of the intermediate member. 
     In yet another embodiment of the present invention, the transmission further comprises a hydraulic fluid pump fixed to the transmission housing and drivingly connected to a torque converter or an engine. The hydraulic fluid pump provides a pressurized hydraulic fluid to a hydraulic control system of the transmission. 
     In yet another embodiment of the present invention, the transmission further comprises a first speed sensor assembly, a second speed sensor assembly, and a third speed sensor assembly each having a speed sensor fixed to the transmission housing and a speed sensor ring rotatably fixed to at least one of the interconnecting members, the input member, and the output member. 
     In yet another embodiment of the present invention, the first speed sensor assembly has a first speed sensor ring rotatably fixed to the input member, the second speed sensor assembly has a second speed sensor ring rotatably fixed to the second interconnecting member, and the third speed sensor assembly has a third speed sensor ring rotatably fixed to the output member. 
     Further features, aspects and advantages of the present invention will become apparent by reference to the following description and appended drawings wherein like reference numbers refer to the same component, element or feature. 
    
    
     
       DRAWINGS 
       The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way; 
         FIG. 1  is a schematic view of an embodiment of an eight speed transmission according to the present invention; 
         FIG. 2A  is a cross section of an input shaft and a shaft or interconnecting member illustrating a fluid routing system for an eight speed transmission in accordance with an embodiment of the present invention; 
         FIG. 2B  is a cross section of the input shaft taken along the line  2 B- 2 B in  FIG. 2A ; 
         FIG. 3A  is a cross section of the input shaft and the shaft or interconnecting member illustrating a fluid routing system for an eight speed transmission in accordance with an embodiment of the present invention wherein the cross section is axially rotated 120° from the cross section taken in  FIG. 2A ; 
         FIG. 3B  is a cross section of the input shaft taken along the line  3 B- 3 B in  FIG. 3A ; 
         FIG. 4  is a diagram showing speed sensor locations for providing an intermediate speed sensor; and 
         FIG. 5  is a schematic view of an embodiment of an eight speed transmission according to the present invention showing an off-axis hydraulic fluid pump. 
     
    
    
     DETAILED DESCRIPTION 
     The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
     Referring to the drawings, wherein like reference numbers refer to like components, in  FIG. 1  a multi-speed transmission  10  is illustrated. The transmission  10  includes an input member  12  and an output member  14 . In the present embodiment, input member  12  and output member  14  are shafts, and will be referred to as such. Those skilled in the art will appreciate that the input and output members  12 ,  14  may be components other than shafts. The input shaft  12  is continuously connected to an engine (not shown) or torque converter  11 . The output shaft  14  is continuously connected with the final drive unit or transfer case (not shown). 
     In a preferred embodiment of the present invention, the transmission  10  includes four planetary gear sets  16 ,  18 ,  20  and  22 . The planetary gear sets  16 ,  18 ,  20  and  22  are connected between the input shaft  12  and the output shaft  14 . 
     The first planetary gear set  16  includes a sun gear member  24 , a ring gear member  26  and a carrier member  28  that rotatably supports a set of planet gears  30 . Sun gear member  24  is connected for common rotation with a first shaft or interconnecting member  32 . Ring gear member  26  is connected for common rotation with a second shaft or interconnecting member  34 . Carrier member  28  is connected for common rotation with a third shaft or member  36 . Planet gears  30  are each configured to intermesh with both the sun gear member  24  and the ring gear member  26 . 
     The second planetary gear set  18  includes a sun gear member  42 , a ring gear member  44  and a carrier member  46  that rotatably supports a set of planet gears  48 . Sun gear member  42  is connected for common rotation with the first shaft or interconnecting member  32 . Ring gear member  44  is connected for common rotation with a fourth shaft or interconnecting member  50 . Carrier member  46  is connected for common rotation with the input shaft  12 . Planet gears  48  are each configured to intermesh with both the sun gear member  42  and the ring gear member  44 . 
     The third planetary gear set  20  includes a sun gear member  52 , a ring gear member  54  and a carrier member  56  that rotatably supports a set of planet gears  58 . Sun gear member  52  is connected for common rotation with the fourth shaft or interconnecting member  50 . Ring gear member  54  is connected for common rotation with a fifth shaft or interconnecting member  60 . Carrier member  56  is connected for common rotation with a sixth shaft or interconnecting member  62 . Planet gears  58  are each configured to intermesh with both the sun gear member  52  and the ring gear member  54 . 
     The fourth planetary gear set  22  includes a sun gear member  72 , a ring gear member  74  and a carrier member  76  that rotatably supports a set of planet gears  78 . Sun gear member  72  is connected for common rotation with a seventh shaft or interconnecting member  64 . Ring gear member  74  is connected for common rotation with the third shaft or interconnecting member  36 . Carrier member  76  is connected for common rotation with the output shaft  14  and the sixth shaft or interconnecting member  62 . Planet gears  78  are each configured to intermesh with both the sun gear member  72  and the ring gear member  74 . 
     The transmission  10  includes a variety of torque-transmitting mechanisms or devices allowing for selective coupling of shafts or interconnecting members, members of the planetary gear sets and the transmission housing  100 . More specifically, transmission  10  includes a first clutch  80 , a second clutch  82 , a third clutch  84 , a first brake  90  and a second brake  92 . For example, first clutch  80  is selectively engageable to connect the seventh shaft or interconnecting member  64  to the input shaft  12 . Second clutch  82  is selectively engagable to connect the seventh shaft or interconnecting member  64  to the fourth shaft or interconnecting member  50 . Third clutch  84  is selectively engagable to connect the fifth shaft or interconnecting member  60  to the seventh shaft or interconnecting member  64 . First brake  90  is selectively engagable to connect the second shaft or interconnecting member  34  to the transmission housing  100  to restrict rotation of the second shaft or interconnecting member  34  relative to the transmission housing  100 . Second brake  92  is selectively engagable to connect the first shaft or interconnecting member  32  to a transmission housing  100  to restrict rotation of the first shaft or interconnecting member  32  relative to the transmission housing  100 . 
     The transmission  10  is capable of transmitting torque from the input shaft  12  to the output shaft  14  in at least eight forward torque ratios and one reverse torque ratio. Each of the forward torque ratios and the reverse torque ratios are attained by engagement of one or more of the torque-transmitting mechanisms (i.e. first clutch  80 , second clutch  82 , third clutch  84 , first brake  90  and second brake  92 ). Those skilled in the art will readily understand that a different speed ratio is associated with each torque ratio. Thus, at least eight forward speed ratios and at least one reverse speed ratio may be attained by the transmission  10 . 
     With continuing reference to  FIG. 1 , the location of the brakes  90 ,  92  and clutches  80 ,  82 ,  84  along the input shaft  12  and relative to the planetary gear sets  16 ,  18 ,  20 ,  22  will now be described. The first and second brakes  90 ,  92  are arranged coaxially with the input shaft  12  and the first brake  90  is disposed axially rearward of the second brake  92 . The torque converter  11  is disposed at a front end  10 A of the transmission  10 . The first and second brakes  90 ,  92  are supported by a center support assembly  101  of the transmission housing  100 . The center support assembly  101  is located between the second planetary gear set  18  and the first planetary gear set  16 . The first brake  90  includes an actuating assembly  90 A and a clutch pack  90 B. The actuating assembly  90 A of the first brake  90  includes a brake piston  104 , a first apply chamber  102 , a second apply chamber  106 , and a dam chamber  110 . The clutch pack  90 B of the first brake  90  includes a plurality of clutch plates  107  secured to the center support  101 . Upon pressurization of the apply chambers  102 ,  106 , the brake piston  104  is forced to engage the clutch plates  107  and the second shaft or interconnecting member  34 . The second brake  92  includes an actuating assembly  92 A and a clutch pack  92 B. The actuating assembly  92 A of the second brake  92  includes a brake piston  114 , an apply chamber  112  and a spring  120 . The clutch pack  92 B of the second brake  92  includes a plurality of clutch plates  109  secured to the center support  101 . Upon pressurization of the apply chamber  112 , the brake piston  114  is forced to engage the clutch plates  109  and the first shaft or interconnecting member  32 . 
     The center support  101  of the transmission housing  100  further includes a first apply fluid passage  102 A, a second apply fluid passage  106 A, a third apply fluid passage  112 A and a first dam fluid passage  110 A. The first apply fluid passage  102 A is in communication with the first apply chamber  102  of the first brake  90 . The second apply fluid passage  106 A is in communication with the second apply chamber  106  of the first brake  90 . The first dam fluid passage  110 A is in communication with the dam chamber  110  of the first brake  90 . The third apply fluid passage  112 A is in communication with the apply chamber  112  of the second brake  92 . 
     The first, second, and third clutches  80 ,  82 ,  84  are arranged coaxially with the input shaft  12 . The first clutch  80 , second clutch  82 , and third clutch  84  are disposed between a front wall  103  of the transmission housing  100  and the third planetary gear set  20 . More specifically, the first clutch  80  is adjacent the front wall  103 , the third clutch  84  is adjacent the third planetary gear set  20 , and the second clutch  82  is disposed between the first and third clutches  80 ,  84 . 
     The first clutch  80  includes an actuating assembly  80 A and a clutch pack  80 B. The actuating assembly  80 A of the first clutch  80  includes an apply chamber  130 , a dam chamber  132  and a piston  134 . The actuating assembly  80 A is supported by and rotatably fixed to the input shaft  12 . The clutch pack  80 B includes a plurality of alternating friction disks or rings. The piston  134  of the actuating assembly  80 A engages the clutch pack  80 B to force the plurality of alternating friction disks together to interconnect the planet carrier  46  of the second planetary gear set  18  and input shaft  12  with the seventh shaft or interconnecting member  64 . 
     The second clutch  82  includes an actuating assembly  82 A and a clutch pack  82 B. The actuating assembly  82 A of the first clutch  82  includes an apply chamber  140 , a dam chamber  142  and a piston  144 . The actuating assembly  82 A is supported rigidly by the seventh shaft or interconnecting member  64 . The clutch pack  82 B includes a plurality of alternating friction disks or rings. The piston  144  of the actuating assembly  82 A engages the clutch pack  82 B to interconnect the seventh shaft or interconnecting member  64  and the fourth shaft or interconnecting member  50 . 
     The third clutch  84  includes an actuating assembly  84 A and a clutch pack  84 B. The actuating assembly  84 A of the first clutch  84  includes an apply chamber  150 , a dam chamber  152  and a piston  154 . The actuating assembly  84 A is supported rigidly by the seventh shaft or interconnecting member  64 . The clutch pack  84 B includes a plurality of alternating friction disks or rings. The piston  154  of the actuating assembly  84 A engages the clutch pack  84 B to interconnect the seventh shaft or interconnecting member  64  and the fifth shaft or interconnecting member  60 . 
     Referring now to  FIGS. 2A ,  2 B,  3 A and  3 B, cross-sectional views of the input shaft  12  and the seventh shaft or interconnecting member  64  are illustrated depicting a hydraulic control circuit  200 , in accordance with an embodiment of the present invention. Hydraulic control circuit  200  contains hydraulic fluid that is pressurized by a hydraulic fluid pump (not shown) and generates hydraulic control signals to actuate the first, second and third clutches  80 ,  82 ,  84  and first and second brakes  90 ,  92  ( FIG. 1 ). The hydraulic control circuit  200  includes three bores disposed in the input shaft  12 : a first bore  201 , a second bore  220 , and a third bore  301 . In one embodiment of the present invention, the first, second, and third bores  201 ,  220 ,  301  are disposed longitudinally in the input shaft  12 . Each bore  201 ,  220 ,  301  is disposed 120° from the adjacent bore  201 ,  220 ,  301  as shown in  FIGS. 2B and 3B . The hydraulic control circuit  200  also includes three annular channels  202 ,  222 ,  302  formed by a sleeve shaft  180 , the input shaft  12 , and a plurality of input shaft seals  182 A-C. The sleeve shaft  180  is fixedly attached to the front support  105  of the transmission housing  100 . The first annular channel  202  is defined by the outer surface of the input shaft  12 , the inner surface of the sleeve shaft  180  and the side surfaces of a first input shaft seal  182 A and a second input shaft seal  182 B. The second annular channel  222  is defined by the outer surface of the input shaft  12 , the inner surface of a sleeve shaft  180  and the side surfaces of the second input shaft seal  182 B and a third input shaft seal  182 C. The third annular channel  302  is defined by the outer surface of the input shaft  12 , the inner surface of a sleeve shaft  180  and the side surfaces of the third input shaft seal  182 C and seal  184 A. 
     The hydraulic circuit  200  further includes a fourth apply fluid passage  107  and a second dam fluid passage  113  contained within the front support  105  of the transmission housing  100 . The fourth apply fluid passage  107  is in communication with the apply chamber  130  of the first clutch  80  (see  FIG. 1 ). The second dam fluid passage  113  is in communication with the dam chamber  132  of the first clutch  80  (see  FIG. 1 ) and the third annular channel  302 . 
     The three input shaft seals  182 A-C are disposed coaxially with the input shaft  12  between the sleeve shaft  180  and the input shaft  12  and seals a first end  12 A of the input shaft  12 . The first and second annular channels  202 ,  222  communicate, respectively, with the first and third bores  201 ,  301  through first and third ports  204 ,  304  formed in the first end  12 A of the input shaft  12 . 
     The first bore  201  contains a first plug  246  fixedly disposed at the second end  12 B of the input shaft  12  to seal the first bore  201 . The first bore  201  communicates with the apply chamber  140  of the second clutch  82  (see  FIG. 1 ) through a first apply port  206  of the input shaft  12 , a fourth annular channel  206 A and a first apply side port  326  of the seventh shaft or interconnecting member  64 . The fourth annular channel  206 A is formed by the outer surface of the input shaft  12 , the inner surface of the seventh shaft or interconnecting member  64  and the side surfaces of a first and a second intermediate seal  184 A,  184 B. 
     The second bore  220  communicates with the second dam fluid passage  113  through a first dam port  207  and the third annular channel  302 . The second bore  220  also communicates with the dam chamber  142  of the second clutch  82  (see  FIG. 1 ) through the second dam port  208 , a fifth annular channel  209 , and a first dam side port  328  of the seventh shaft or interconnecting member  64 . The fifth annular channel  209  is formed by the outer surface of the input shaft  12 , the inner surface of the seventh shaft or interconnecting member  64  and the side surfaces of a second and a third intermediate seal  184 B,  184 C. The second bore  220  is open at a second end  12 B of the input shaft  12  communicating with an intermediate bore  64 A disposed in the seventh shaft or interconnecting member  64 . The seventh shaft or interconnecting member  64  includes a second dam side port  64 B that communicate with the intermediate bore  64 A and the dam chamber  152  of the third clutch  84  (see  FIG. 1 ). 
     The third bore  301  contains a second plug  248  fixedly disposed at the second end  12 B of the input shaft  12  to seal the third bore  301 . The third bore  301  communicates with the apply chamber  150  of the third clutch  84  (see  FIG. 1 ) through a second apply port  306  of the input shaft  12 , a sixth annular channel  332 , and a second apply side port  330  of the seventh shaft or interconnecting member  64 . The sixth annular channel  332  is formed by the outer surface of the input shaft  12 , the inner surface of the seventh shaft or interconnecting member  64  and the side surfaces of a third and a fourth intermediate seal  184 C,  184 D. 
     Referring now to  FIG. 4 , a cross section of the transmission  10  is illustrated showing locations for three speed sensor assemblies  410 ,  420 ,  430 . The speed sensors  412 ,  422 ,  432  are fixedly attached to the transmission housing  100 . The speed sensors  412 ,  422 ,  432  are conventional speed sensors such as Hall Effect sensors or variable reluctance sensors and the like. The speed sensor rings  414 ,  424 ,  434  are in close proximity to the speed sensors  412 ,  422 ,  432  and are fixedly attached to one of the rotatable shafts or members of transmission  10 . The speed sensors  412 ,  422 ,  432  detect the presence of the respective speed sensor ring  414 ,  423 ,  434  to count the revolutions of the shaft or interconnecting member to which the speed sensor ring  414 ,  424 ,  434  is attached. Alternatively, the speed sensor rings  414 ,  424 ,  434  are magnetic strips or toothed portions of shafts having magnetic material formed in the rotatable shafts or members of transmission  10 . 
     For example, the first speed sensor  412  is fixedly attached to the transmission housing  100  and the first speed sensor ring  414  is fixedly disposed on the input shaft  12 . The second speed sensor  422  is fixedly disposed on the transmission housing  100  and the second speed ring  424  is fixedly disposed on the third shaft or member  36 . The third speed sensor  432  is fixedly disposed on the transmission housing  100  and the third speed sensor ring  434  is fixedly disposed on the output shaft  14 . 
     Referring now to  FIG. 5 , a cross section of the transmission  10  including an off-axis fluid pump assembly  500  is illustrated and will now be described. Off-axis fluid pump assembly  500  includes a transmission fluid pump  502 , a drive gear or pulley member  504 , a driven gear or pulley member  506 , a pump shaft  508  and a chain or belt  510 . The transmission fluid pump  502  is fixedly attached to the transmission housing  100  or a similar stationary member along an axis “l” that is offset a predefined radial distance “d” from the axis “i” of the input shaft  12 . The drive gear or pulley member  504  is fixedly attached for common rotation with the torque converter  11 . The driven gear or pulley member  506  is fixedly connected for common rotation with the pump shaft  508 . The chain or belt  510  engages both the drive gear or pulley member  504  and the driven gear or pulley member  506  to transfer driving torque from the input shaft  12  to the pump shaft  508 . The pump shaft  508  transfers the driving torque produced in the chain or belt  510  to fluid pump  502 . A stepped ratio may be used between the drive gear or pulley member  504  and the driven gear or pulley member  506  to reduce the amount of energy transferred to the transmission fluid pump  502  thus resulting in a more efficient transmission  10 . The fluid pump assembly  500  provides fluid pressure and flow for transmission  10  function. Driving the fluid pump assembly  500  by a ratio connection allows the transmission  10  to more efficiently provide fluid pressure and flow. 
     The description of the invention is merely exemplary in nature and variations that do not depart from the gist of the invention are intended to be within the scope of the invention. Such variations are not to be regarded as a departure from the spirit and scope of the invention.