Abstract:
A multi-stage transmission includes a first stage, a second stage, a final drive, and at least two torque transmitting devices. The at least two torque transmitting members selective couple the first stage, the second stage and the final drive with each other to produce a reverse gear or one of a plurality of forward gears.

Description:
RELATED APPLICATION 
       [0001]    The present application claims the benefit of U.S. Provisional Patent Application No. 62/082,424, filed on Nov. 20, 2014. 
         [0002]    The entire contents of the above application are incorporated herein by reference. 
     
    
     FIELD 
       [0003]    The present disclosure relates to a manual transmission for motor vehicles. More specifically, the present disclosure relates to a multi-stage manual transmission. 
       BACKGROUND 
       [0004]    The statements in this section merely provide background information related to the present disclosure and may or may not constitute prior art. 
         [0005]    A typical multiple speed transmission employs a combination of torque transmitting devices and selectively engaged torque transmitting devices that achieve a plurality of speed or gear ratios. The arrangement of the various components of a transmission, generally, is dictated by packaging requirements, cost and desired speed ratios. 
         [0006]    While current transmissions achieve their intended purpose, the need for new and improved transmission configurations which exhibit improved performance and improved packaging, primarily reduced size and weight, remains constant. 
       SUMMARY 
       [0007]    The present invention provides an improved multi-stage transmission. 
         [0008]    Accordingly, in one aspect of the invention, a multi-stage transmission includes a first stage, a second stage, a final drive, and at least two torque transmitting devices. The at least two torque transmitting devices selectively couple the first stage, the second stage and the final drive with each other to produce a reverse gear or one of a plurality of forward gears. 
         [0009]    In another aspect, a multi-stage transmission includes a first stage with a first torque transmitting device and a second torque transmitting device, a second stage with a third torque transmitting device, and a final drive. The torque transmitting devices selectively couple the first stage, the second stage and the final drive with each other to produce a reverse gear or one of a plurality of forward gears. 
         [0010]    In yet another aspect, a multi-stage transmission includes a first stage with a first torque transmitting device and a second torque transmitting device, as well as four gear sets; a second stage with a third torque transmitting device and a third torque transmitting device, as well as one gear set; and a final drive with one gear set. The torque transmitting devices selectively couple the first stage, the second stage and the final drive with each other to produce a reverse gear or one of a plurality of forward gears 
         [0011]    Any of the aforementioned multi-stage transmissions may be further characterized by one or any combination of the features described herein, such as, for example: one of the at least two torque transmitting devices is associated with the first stage, and another of the at least two torque transmitting devices is associated with the second stage; the first stage includes two torque transmitting devices; the second stage includes a third torque transmitting device; the at least two torque transmitting devices are synchronizers; the at least two torque transmitting devices are clutches; the transmission has six forward gears; the first stage has four gear sets; the second stage has one gear set; and the final drive has one gear set. 
         [0012]    Further features, advantages, and areas of applicability will become apparent from the description provided herein. It should be understood that the description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0013]    The drawings described herein are for illustration purposes only and are not intended to limit the scope of the present disclosure in any way. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like reference numerals designate corresponding parts throughout the views. In the drawings: 
           [0014]      FIG. 1  is a schematic diagram of a multi-stage transmission in neutral in accordance with the principles of the present invention; 
           [0015]      FIG. 2  is a schematic diagram of the multi-stage transmission in a reverse gear in accordance with the principles of the present invention; 
           [0016]      FIG. 3  is a schematic diagram of the multi-stage transmission in a first forward gear in accordance with the principles of the present invention; 
           [0017]      FIG. 4  is a schematic diagram of the multi-stage transmission in a second forward gear in accordance with the principles of the present invention; 
           [0018]      FIG. 5  is a schematic diagram of the multi-stage transmission in a third forward gear in accordance with the principles of the present invention; 
           [0019]      FIG. 6  is a schematic diagram of the multi-stage transmission in a fourth forward gear in accordance with the principles of the present invention; 
           [0020]      FIG. 7  is a schematic diagram of the multi-stage transmission in a fifth forward gear in accordance with the principles of the present invention; 
           [0021]      FIG. 8  is a schematic diagram of the multi-stage transmission in a sixth forward gear in accordance with the principles of the present invention; 
           [0022]      FIGS. 9A and 9B  are schematic diagrams illustrating the operation of a pair of torque transmitting devices for the multi-stage transmission in accordance with the principles of the present invention; and 
           [0023]      FIG. 10  is a table presenting the various combinations of gear sets of the multi-stage transmission to achieve each of the available forward and reverse gears. 
       
    
    
     DETAILED DESCRIPTION 
       [0024]    The following description is merely exemplary in nature and is not intended to limit the present disclosure, application, or uses. 
         [0025]    Referring now to the drawings, a multi-stage transmission for a motor vehicle embodying the principles of the present invention is illustrated in  FIG. 1  and designated at  10 . The multi-stage transmission  10  includes a first stage  12 , a second stage  14  and a final drive  16 . 
         [0026]    The first stage  12  includes a first gear set  22  with a first member  28  and a second member  30 , a second gear set  24  with a third member  32  and a fourth member  34 , a third gear set  26  with a fifth member  36  and a sixth member  38 , and a fourth (or reverse) gear set  46  with a seventh member  50  and an eighth member  52  as well as an idler  54  that couples seventh member  50  to the eight member  52 . The first stage  12  also includes a first synchronizer  42  operated with a lever  43  and a second synchronizer  44  operated with a lever  45 . As described in detail below the synchronizers  42  and  44  selectively couple the first gear set  22 , the second gear set  24 , the third gear set  26  or the fourth gear set  48  to an input shaft  18  with a first interconnecting member or shaft  40 , which couples the first stage  12  with the second stage  14 . 
         [0027]    The second stage  14  includes a fifth gear set  48  with a ninth member  56  and a tenth member  58  as well as an idler  57  that couples the ninth member  56  with the tenth member  58 . The second stage also includes a third synchronizer  64  that selectively couples the fifth gear set  48  with the interconnecting member or shaft  40  and an interconnecting member or shaft  60  or an interconnecting member or shaft  62 . 
         [0028]    The final drive  16  includes a sixth gear set  67  with an eleventh member  68 , a twelfth member  70  and a thirteenth member  72 . The eleventh member  68  is coupled to the first interconnecting member or shaft  60  and the thirteenth member  72  is coupled to the second interconnecting member or shaft  62 . A drive shaft  20  is connected to the twelfth member  70  which in turn couples with the eleventh member  68  and the thirteenth member  72 . 
         [0029]    The multi-stage transmission is shown in neutral in  FIG. 1 . To operate the multi-stage transmission  10  in a reverse gear ( FIG. 2 ), the first synchronizer  42  is unengaged from either the first gear set  22  or the second gear set  24  and the third synchronizer  64  is unengaged from the fifth gear set  48 , while the first interconnecting member or shaft  40  is coupled to the second interconnecting member or shaft  60 . The lever  45  is operated to engage the second synchronizer  44  with the seventh member  50  of the fourth gear set  46 . Since the idler  54  couples the seventh member  50  with the eighth member  52 , the fourth gear set  46  couples the input shaft  18  with the first interconnecting member or shaft  40  when the multi-stage transmission  10  is in reverse gear. Accordingly, when the multi-stage transmission  10  is in reverse gear, the input shaft  18  receives input torque that is transmitted through the fourth gear set  46 , the first interconnecting member of shaft  40 , the second interconnecting member or shaft  60 , the eleventh member  68 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in reverse gear is indicated by the arrows in  FIG. 2 . 
         [0030]    To operate the multi-stage transmission  10  in a first forward gear, as shown in  FIG. 3 , the second synchronizer  44  is unengaged from either the third gear set  26  or the fourth gear set  46  and the third synchronizer  64  is unengaged from the fifth gear set  48 , while the first interconnecting member or shaft  40  is coupled to the second interconnecting member or shaft  60 . The lever  43  is operated to engage the first synchronizer  42  with the first member  28  of the first gear set  22 . Since the first member  28  couples with the second member  30 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the first gear set  22  when the multi-stage transmission  10  is in first forward gear. Accordingly, when the multi-stage transmission  10  is in first forward gear, the input shaft  18  receives input torque that is transmitted through the first gear set  22 , the first interconnecting member of shaft  40  and the second interconnecting member or shaft  60 , the eleventh member  68 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in first forward gear is indicated by the arrows in  FIG. 3 . 
         [0031]    To operate the multistage transmission  10  in a second forward gear, as shown in  FIG. 4 , the second synchronizer  44  is unengaged from either the third gear set  26  or the fourth gear set  46  and the third synchronizer  64  is unengaged from the fifth gear set  48 , while the first interconnecting member or shaft  40  is coupled to the second interconnecting member or shaft  60 . The lever  43  is operated to engage the first synchronizer  42  with the third member  32  of the second gear set  24 . Since the third member  32  couples with the fourth member  34 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the second gear set  24  when the multi-stage transmission  10  is in second forward gear. Accordingly, when the multi-stage transmission  10  is in second forward gear, the input shaft  18  receives input torque that is transmitted through the second gear set  24 , the first interconnecting member of shaft  40  and the second interconnecting member or shaft  60 , the eleventh member  68 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in second forward gear is indicated by the arrows in  FIG. 4 . 
         [0032]    To operate the multistage transmission  10  in a third forward gear, as shown in  FIG. 5 , the first synchronizer  42  is unengaged from either the first gear set  22  or the second gear set  24  and the third synchronizer  64  is unengaged from the fifth gear set  48 , while the first interconnecting member or shaft  40  is coupled to the second interconnecting member or shaft  60 . The lever  45  is operated to engage the second synchronizer  44  with the fifth member  36  of the third gear set  26 . Since the fifth member  36  couples with the sixth member  38 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the third gear set  26  when the multi-stage transmission  10  is in third forward gear. Accordingly, when the multi-stage transmission  10  is in third forward gear, the input shaft  18  receives input torque that is transmitted through the third gear set  26 , the first interconnecting member of shaft  40  and the second interconnecting member or shaft  60 , the eleventh member  68 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in second forward gear is indicated by the arrows in  FIG. 5 . 
         [0033]    To operate the multistage transmission  10  in a fourth forward gear, as shown in  FIG. 6 , the second synchronizer  44  is unengaged from either the third gear set  26  or the fourth gear set  46 . The lever  43  is operated to engage the first synchronizer  42  with the first member  28  of the first gear set  22 , and the lever  65  is operated to engage the third synchronizer  64  with the ninth member  56  of the fourth gear set  48 , while the first interconnecting member or shaft  40  is uncoupled from the second interconnecting member or shaft  60 , such that the second interconnecting member or shaft  60  is free-wheeling. Since the first member  28  couples with the second member  30 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the first gear set  22  when the multi-stage transmission  10  is in fourth forward gear. Further, since the idler  57  couples the ninth member  56  with the tenth member  58  of the fourth gear set  48 , the first interconnecting member or shaft  40  is coupled to the third interconnecting member or shaft  62  when the multi-stage transmission  10  is in fourth forward gear. Accordingly, when the multi-stage transmission  10  is in fourth forward gear, the input shaft  18  receives input torque that is transmitted through the first gear set  26 , the first interconnecting member of shaft  40 , the fourth gear set  48 , the third interconnecting member or shaft  62 , the thirteenth member  72 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in fourth forward gear is indicated by the arrows in  FIG. 6 . 
         [0034]    To operate the multistage transmission  10  in a fifth forward gear, as shown in  FIG. 7 , the second synchronizer  44  is unengaged from either the third gear set  26  or the fourth gear set  46 . The lever  43  is operated to engage the first synchronizer  42  with the third member  32  of the second gear set  24 , and the lever  65  is operated to engage the third synchronizer  64  with the ninth member  56  of the fourth gear set  48 , while the first interconnecting member or shaft  40  is uncoupled from the second interconnecting member or shaft  60 , such that the second interconnecting member or shaft  60  is free-wheeling. Since the third member  32  couples with the fourth member  34 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the second gear set  24  when the multi-stage transmission  10  is in fifth forward gear. Further, since the idler  57  couples the ninth member  56  with the tenth member  58  of the fourth gear set  48 , the first interconnecting member or shaft  40  is coupled to the third interconnecting member or shaft  62  when the multi-stage transmission  10  is in fifth forward gear. Accordingly, when the multi-stage transmission  10  is in fifth forward gear, the input shaft  18  receives input torque that is transmitted through the second gear set  24 , the first interconnecting member of shaft  40 , the fourth gear set  48 , the third interconnecting member or shaft  62 , the thirteenth member  72 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in fifth forward gear is indicated by the arrows in  FIG. 7 . 
         [0035]    To operate the multistage transmission  10  in a sixth forward gear, as shown in  FIG. 8 , the first synchronizer  42  is unengaged from either the first gear set  22  or the second gear set  24 . The lever  45  is operated to engage the second synchronizer  44  with the fifth member  36  of the third gear set  26 , and the lever  65  is operated to engage the third synchronizer  64  with the ninth member  56  of the fourth gear set  48 , while the first interconnecting member or shaft  40  is uncoupled from the second interconnecting member or shaft  60 , such that the second interconnecting member or shaft  60  is free-wheeling. Since the fifth member  36  couples with the sixth member  38 , the input shaft  18  is coupled to the first interconnecting member or shaft  40  through the third gear set  26  when the multi-stage transmission  10  is in sixth forward gear. Further, since the idler  57  couples the ninth member  56  with the tenth member  58  of the fourth gear set  48 , the first interconnecting member or shaft  40  is coupled to the third interconnecting member or shaft  62  when the multi-stage transmission  10  is in sixth forward gear. Accordingly, when the multi-stage transmission  10  is in sixth forward gear, the input shaft  18  receives input torque that is transmitted through the third gear set  26 , the first interconnecting member of shaft  40 , the fourth gear set  48 , the third interconnecting member or shaft  62 , the thirteenth member  72 , the twelfth member  70  and the drive shaft  20  which in turn provides drive torque to, for example, drive wheels of the motor vehicle. The torque path for the multi-stage transmission  10  in fifth forward gear is indicated by the arrows in  FIG. 8 . 
         [0036]    Referring now to  FIG. 10 , the sequence of the activation or engagement of the first gear set  22 , the second gear set  24 , the third gear set  26  and the fourth gear set  48  which provide six forward speeds or gear ratios and reverse is illustrated. More specifically,  FIG. 10  is a truth table which presents the various combinations of the gear sets  22 ,  24 ,  26  and  48  to achieve six forward speeds and reverse. Actual numerical gear ratios of the various gear states are also presented although it should be appreciated that these numerical values are just examples and that they may be adjusted over significant ranges to accommodate various applications and operational criteria of the multi-stage transmission  10 . Other gear ratios are achievable depending, for example, on the gear diameter, gear teeth count and gear configuration selected. 
         [0037]    Note that the multi-stage transmission  10  is not limited to the gear sets described above to provide six forward speeds and one reverse speed. For example, the first stage  12  may include fewer or greater than four gear sets and fewer or greater than two synchronizers, and the second stage  14  may include greater than one gear set and greater than one synchronizer to provide less than or greater than six forward speeds. For example, the fourth (or reverse) gear set  46  can be included in the second stage  14 , which may include an additional synchronizer. Hence, in some arrangements, the first stage  12  can include three gear sets and two synchronizers, and the second stage  14  can include two gear sets and two synchronizers. 
         [0038]    In another arrangement, at least two of the first synchronizer  42 , the second synchronizer  44  and the third synchronizer  64  are replaced with a pair of torque transmitting devices such as a first clutch  108  and a second clutch  110  operated in a system  100  shown in  FIGS. 9A and 9B . The system  100  includes an actuator  102 , such as, an electric solenoid actuator, a first piston  104  and a second piston  106 . The first piston  104  includes a sliding member  114  disposed in a housing  116  and connected to the actuator  102  with a first interconnecting member or rod  112 . A biasing member such as a spring  118  also disposed in the housing  116  applies a biasing force on the sliding member  114  toward the actuator  102 . The first piston  104  is in fluid communication with the second piston  106  through a conduit  124 . The first piston  104  further includes an exhaust  120  and an inlet  122 . 
         [0039]    The second piston  106  includes a sliding member  126  disposed in a housing  128  and is coupled to the first clutch  108  and the second clutch  110  with a second interconnecting member or rod  130  and a set of links  131 ,  132  and  133 . Specifically, the link  131  is coupled to the second clutch  110 , the link  133  is coupled to the first clutch, and the interconnecting member  130  is coupled to the links  131  and  132  which in turn is coupled to the link  133 . The link  132  supported at a pivot or fulcrum  134 , and a biasing member such as a spring  136  is positioned between the link  132  and a stationary member  138  as shown in  FIGS. 9A and 9B . 
         [0040]    The system  100  enables operating the two clutches  108  and  110  with a single actuator such as the actuator  102 . When the actuator  102  is turned on ( FIG. 9A ), the first interconnecting member or rod  112  is pushed toward the first piston  104 . Hence, the sliding member  114  is pushed away from the actuator  102  toward the spring  118  while gas such as air flows from the second piston  106  flows to the first piston  104  through the conduit  124  to fill the expanding volume in the housing  116 . The gas also escapes from the first piston  104  through the exhaust  120 . Movement of the sliding member  114  toward the spring  118  compresses the spring  118 , and gas flowing from the second piston  106  causes the sliding member  126  to move toward the clutches  108  and  110 . The movement of the sliding member  126  also pushes the second interconnecting member or rod  130  toward the clutches  108  and  110  as well. As this occurs, the link  131  is pushed toward the second clutch  110  to engage the second clutch  110  while the link  132  rotates counterclockwise about the pivot  134 . The rotation of the link  132  compresses the spring  136  against the stationary member  138  and pulls the link  133  away from the first clutch  108  to disengage the first clutch  108 . 
         [0041]    When the actuator  102  is turn off ( FIG. 9B ), the biasing force imparted by the spring  118  pushes the first interconnecting member or rod  112  toward the actuator  102  while gas such as compressed air flows into the housing  116  though the inlet  122 . The gas also flows to the second piston  106  through the conduit  124 . As gas flows into the housing  128  of the second piston  106 , the sliding member  126  is pushed away from the clutches  108  and  110 . The movement of the sliding member  126  pulls the second interconnecting member or rod  130  away from the clutches  108  and  110  as well. As this occurs, the link  131  and the lower portion of the link  132  below the pivot  134  are pulled away from the second clutch  110  while the biasing force imparted by the spring  136  on the link  132  pushes on the lower portion of the link  132  which causes the link  132  to rotate clockwise. Clockwise movement of the link  132  about the pivot  134  results in movement of the link  133  toward the first clutch  108  to engage the first clutch  108  and movement of the link  131  away from the second clutch  110  to disengage the second clutch  110 . 
         [0042]    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.