Patent Publication Number: US-2006016285-A1

Title: Shift operating apparatus for a vehicle

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      This application is based on and claims priority under 35 U.S.C. §119 with respect to Japanese Patent Application 2004-211946, filed on Jul. 20, 2004, the entire content of which is incorporated herein by reference.  
     FIELD OF THE INVENTION  
      This invention generally relates to a shift operating apparatus which is mounted on a vehicle.  
     BACKGROUND  
      In order to improve fuel efficiency, and a driving performance, of a vehicle, recent requirements have led to automation of a shift operating apparatus applied to a conventional gear-type manual transmission. Especially, as is disclosed in JP56(1981)-127842A and DE3530017, a twin clutch-type automated manual transmission has been suggested, the transmission which is provided with two clutch mechanisms (a first clutch and a second clutch) for transmitting driving power from an engine to the transmission, and two input shafts (a first input shaft and a second input shaft). In this type of transmission, the first clutch is engaged with the first input shaft, while the second clutch is engaged with the second input shaft. On the first input shaft, there are odd numbered gear trains (a first shift stage gear train, a third shift stage gear train and a fourth shift stage gear train) mounted, while, on the second input shaft, there are even numbered gear trains (a second shift stage gear train, a fourth shift stage gear train and a sixth shift stage gear train) mounted.  
      According to the above-described shift operating apparatus for a vehicle, which includes the twin clutch-type automated manual transmission, when a shift stage established in the transmission is switched from a first shift stage to a second shifts stage while the frictional slip-type first clutch is frictionally being engaged with a clutch mating, the second clutch is frictionally engaged with a clutch mating while the first clutch is still being frictionally engaged with the clutch mating. Therefore, when a shift stage in the transmission is switched, it is possible to transmit, via the first shift stage gear train and the second shift stage gear train, driving force of an engine to an output shaft of the transmission, thereby enabling to transmit driving torque to the output shaft of the transmission via both the first input shaft and the second input shaft. As a result, when a shift stage in the transmission is switched, torque transmission to the output shaft is not interrupted, and a shift operation can be effectively implemented while curving interruption of torque transmission.  
      As one of a shift control mechanism, WO01/84019 discloses a shift operating apparatus for a vehicle, the apparatus which is provided with a group of operating members, which is configured with plural operating members that are arranged in parallel to one another along a select direction, a switching engagement body, which can be frictionally engaged with the respective operating members and can move both in select and shift directions, a select actuator, which moves the switching engagement body in a select direction in such a manner that the switching engagement body is engaged with one operating member from among the group of operating members, and a shift actuator, which moves the switching engagement body in a shift direction and moves the one operating member, which has been engaged with the switching engagement body, in a shift direction.  
      As is illustrated in  FIG. 14 , according to a conventional technology disclosed in WO01/84019, when a first operating member  11   w  moves in a direction of arrow C 1 , a first shift stage is established, while, when the first operating member  11   w  moves in a direction of arrow C 2 , a third shift stage is established. When a second operating member  12   w  moves in the direction of arrow C 2 , a second shift stage is established, while, when the second operating member  12   w  moves in the direction of arrow C 1 , a fourth shift stage is established. When a third operating member  13   w  moves in the direction of arrow C 2 , a fifth shift stage is established, while, when the third operating member  13   w  moves in the direction of arrow C 1 , a seventh shift stage is established. When a fourth operating member  14   w  moves in the direction of arrow C 2 , a reverse shift stage is established, while, when the fourth operating member  14   w  moves in the direction of arrow C 1 , a sixth shift stage is established. Herein, the first operating member  11   w , the second operating member  12   w , the third operating member  13   w  and the fourth operating member  14   w  are each provided with a fitting groove  22   w  which an inner lever portion  20   w  is fitted into and is engaged with.  
       FIG. 14  illustrates a first shift stage being established with the first operating member  11   w , which has been moved by the inner lever portion  20   w  in the direction of arrow C 1 . As is apparent from  FIG. 14 , when a shift stage in a transmission is switched from a first shift stage to a second shit stage, at a time that the first operating member  11   w  has moved in the direction of arrow C 1  so as to establish the first shift stage, the inner lever portion  20   w  is moved in a direction of arrow E 2  so as return to a neutral position (N). After returning to the neutral position (N), the inner lever portion  20   w  is moved in a direction of arrow E 3  so as to be positioned at the groove  22   w  of the second operating member  12   w . After being seated at the fitting groove  22   w  of the second operating member  12   w , the inner lever portion  20   w  is moved in a direction of arrow E 4 , and the second operating member  12   w  is then moved in the direction of arrow C 2 .  
      According to the above-described technology, it is necessary to once return the inner lever portion  20   w  to the neutral position (N), wherein an operating distance which the inner lever portion  20   w  has to move may be increased. Therefore, it may require a relatively long operating time for the inner lever portion  20   w , and then for a shift operation of a vehicle. Consideration should be hence given to a limited response in a shift operation, the limited response that occurs due to the above description.  
      The present invention has been made in view of the above circumstances, and provides a shift operating apparatus for a vehicle by which it is possible to improve a response in a shift operation.  
     SUMMARY OF THE INVENTION  
      According to an aspect of the present invention, a shift operating apparatus for a vehicle includes a group of operating members including: plural operating members and arranged all in parallel in a select direction; a switching engagement body engageable with the respective plural operating members and movable in a shift direction and in the select direction; a select operating means for moving the switching engagement body in the select direction and for engaging the switching engagement body with one operating member from among the plural operating members to establish one shift stage; a shift operating means for moving the one operating member, which has been engaged with the switching engagement body, in the shift direction by moving the switching engagement body in the shift direction; toothed portions respectively formed on the respective operating members, tooth phases of the respective toothed portions being mutually matched in the shift direction when the operating members are positioned at a neutral position; and an engagement gear included in the switching engagement body and engageable with the respective toothed portions of the respective operating members. When one of the operating members has moved in the shift direction from the neutral position, the tooth phase of the toothed portion of the one of the operating members is matched with the tooth phases of the toothed portions of the other operating members. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
      The foregoing and additional features and characteristics of the present invention will become more apparent from the following detailed description considered with reference to the accompanying drawings, wherein:  
       FIG. 1  is a view schematically illustrating a shift operating apparatus for a vehicle which is provided with a twin clutch-type manual transmission;  
       FIG. 2  is a view illustrating an H-shift range of the transmission;  
       FIG. 3  is a view illustrating a relevant portion in the vicinity of a shift and select shaft of the shift operating apparatus according to a first embodiment of the present invention;  
       FIG. 4  illustrates an engagement condition between an engagement gear of the shift and select shaft and a first toothed portion of the first operating member which is positioned at a neutral position;  
       FIG. 5  illustrates an engagement condition between the engagement gear of the shift and select shaft and the first toothed portion of the first operating member which is positioned at a shift position;  
       FIG. 6  is a view illustrating a vicinity of the shift and select shaft;  
       FIG. 7  is a view schematically illustrating a structure of a group of operating members which are all positioned at a neutral position;  
       FIG. 8  is a view schematically illustrating the first operating member moved in a shift direction to establish a first shift stage;  
       FIG. 9  is a view schematically illustrating a second operating member moved in a shift direction to establish a second shift stage while the first operating member has moved in the shift direction;  
       FIG. 10  is a view schematically illustrating the first operating member moved in a shift direction while the second operating member has moved in the shift direction;  
       FIG. 11  is a view illustrating a relevant portion in the vicinity of a shift and select shaft of a shift operating apparatus according to a second embodiment of the present invention;  
       FIG. 12  illustrates an engagement condition between an engagement gear of the shift and select shaft and a first toothed portion of a first operating member according to the second embodiment;  
       FIG. 13  is a view illustrating an engagement gear of the shift and select shaft and a lock toothed portion according to the second embodiment; and  
       FIG. 14  is a view schematically illustrating a structure of a group of operating members according to a known work. 
    
    
     DETAILED DESCRIPTION  
      Embodiments of the present invention will be described hereinbelow in detail with reference to the accompanying drawings.  
      As is illustrated in  FIG. 1 , according to a first embodiment of the present invention, a transmission apparatus for a vehicle includes a first clutch  201  configured to be frictionally engaged with a clutch mating  550 , a second clutch  202  configured to be frictionally engaged with the clutch mating  550 , a first input shaft  301  which is connected to the first clutch  201 , a second input shaft  302  which is connected to the second clutch  202 , and an output shaft  305  which rotates in response to rotation, of the first input shaft  301 , or of the second input shaft  302 , or in response to rotation of both the first and second input shafts  301  and  302 . The first input shaft  301  is coaxially arranged inside of a hollow cylinder  304  of the second input shaft  302 .  
      On the first input shaft  301 , odd-numbered gear trains are mounted, which are a first shift stage gear train  401 , a third shift stage gear train  403 , a fifth shift stage gear train  405 , and a seventh shift stage gear train  407 . On the second input shaft  302 , even-numbered gear trains are mounted, which are a second shift stage gear train  402 , a fourth shift stage gear train  404  and a sixth shift stage gear train  406 . On the output shaft  305 , driven gears  451 ,  452 ,  453 ,  454 ,  455 ,  456 ,  457  and  458  are mounted. A drive shaft  510  is driven via a differential gear  500  and is mounted, thereon, with vehicle wheels  511  and  512 .  
      When the first clutch  201  is frictionally engaged with the clutch mating  550 , a crankshaft  520  at an engine side is connected to the first input shaft  301  via the first clutch  201  being frictionally engaged. In this case, a driving force transmission path is established via the first clutch  201  between the crankshaft  520  and the first input shaft  301 , wherein rotational driving force of the crankshaft  520  is transmitted to the first input shaft  301  via the first clutch  201 . As a result, the first input shaft  301  rotates. On the other hand, when the second clutch  202  is frictionally engaged with the clutch mating  550 , the crankshaft  520  at an engine side is connected to the second input shaft  302  via the second clutch  202  being frictionally engaged. In this case, a driving force transmission path is established via the second clutch  202  between the crankshaft  520  and the second input shaft  302 , wherein rotational driving force of the crankshaft  520  is transmitted to the second input shaft  302  via the second clutch  202 . As a result, the second input shaft  302  rotates.  
      A shift operation is performed via a hub sleeve  601  or  602 . Going back to  FIG. 1 , a transmission path  100 , which is denoted with a solid line in  FIG. 1 , represents a torque transmission path established when a vehicle drives at a first shift stage with the first clutch  201  being engaged. On the other hand, a transmission path  150 , which is denoted with a broken line in  FIG. 1 , represents a torque transmission path established when a vehicle drives at a second shift stage with the second clutch  202  being engaged.  
      According to a twin clutch-type transmission apparatus according to the first embodiment of the present invention, when a shift stage in a transmission is switched from a first shift stage to a second shift stage, frictional engagement of the second clutch  202  is executed when the first clutch  201  has been frictionally engaged. Therefore, while an engine torque is being transmitted to the output shaft  305  via the first shift stage gear train  401  mounted on the first input shaft  301 , it is possible to transmit an engine torque to the output shaft  305  also via the second shift stage gear train  402  mounted on the second input shaft  302 . As a result, even when a shift stage in a transmission is switched from the first shift stage to the second shift stage, it is possible to restrain interruption of torque transmission from the crankshaft  520  to the output shaft  305 , and to perform effectively a shift operation.  
      As described above, according to the first embodiment of the present invention, even when a shift operation is required, it is possible to transmit torque with high transmission efficiency, and to improve fuel efficiency while a vehicle is driving. This results from the frictional engagement disc-type clutches  201  and  202 . That is, even when torque transmission is implemented via both the first clutch  201  and the second clutch  202 , the first and second clutches  201  and  202  are engaged with the clutch mating  550  in a slip manner, wherein it is possible to absorb a rotational speed difference between the first and second clutches  201  and  202 , relative to the clutch mating  550 . Further, when a shift operation from the first shift stage to the second shift stage is completed, the first clutch  201  is released from being frictionally engaged, while the second clutch  202  is maintained to be frictionally engaged.  
      When a shift operation from a second shift stage to a third shift stage is performed, frictional engagement of the first clutch  201  is executed when the second clutch  202  has been frictionally engaged. Therefore, while an engine torque is being transmitted to the output shaft  305  via the second shift stage gear train  402  mounted on the second input shaft  302 , it is possible to transmit an engine torque to the output shaft  305  also via the third shift stage gear train  403  mounted on the first input shaft  301 . When a shift operation from the second shift stage to the third shift stage is completed, the second clutch  202  is released from being frictionally engaged, while the first clutch  201  is maintained to be frictionally engaged.  
      As is illustrated in  FIG. 2 , according to the first embodiment, select directions of a select operation are denoted with arrows S 1  and S 2 , while shift directions of a shift operation are denoted with arrows C 1  and C 2 . As is illustrated in  FIG. 2 a  first shift stage, a fourth shift stage, a seventh shift stage, and a sixth shift stage are in parallel lined in the select direction of arrow S 1 , while a third shift stage, a second shift stage, a fifth shift stage and a reverse shift stage are in parallel lined in the select direction of arrow S 1 . Moreover, in the shift directions of arrows C 1  and C 2 , the first shift stage is lined up with the third shift stage, the fourth shift stage is lined up with the second shift stage, the sevenths shift stage is lined up with the fifth shift stage, the sixth shift stage is lined up with the reverse shift stage. However, the above alignment of the shift stages is regarded as illustrative rather than restrictive. Therefore, the other alignments thereof are also applicable.  
      As is illustrated in  FIG. 3 , the shift operating apparatus for a vehicle according to the first embodiment of the present invention is further provided with a group of operating members  1 , a switching engagement body  3  engageable with the group of operating members  1 , a shift and select shaft  30  employed as a main element of the switching engagement body  3 , a select actuator  5  for moving the shift and select shaft  30  in the select direction of either arrows S 1  or S 2 , and a shift actuator  6  for moving the switching engagement body  3  in the shift direction of either arrows C 1  or C 2 .  
      The group of operating members  1  includes a first operating member  11 , a second operating member  12 , a third operating member  13  and a fourth operating member  14 , all of which are aligned in parallel in the select direction. The operating members  11 - 14  are shift fork shafts which are respectively formed integrally with shift heads. According to the first embodiment of the present invention, as is obvious from  FIG. 7 , the first and third shift stages are defined by the first operating member  11 , the fourth and second shift stages are established by the second operating member  12 , the seventh and fifth shift stages are established by the third operating member  13 , and the sixth and reverse shift stages are established by the fourth operating member  14 .  
      Herein, with reference to  FIGS. 7 and 8 , when the first operating member  11  moves in the direction of arrow C 1 , a first shift stage is established, while, when the first operating member  11  moves in the direction of arrow C 2 , a third shift stag is established. When the second operating member  12  moves in the direction of arrow C 1 , a fourth shift stage is established, while, when the second operating member  12  moves in the direction of arrow C 2 , a second shift stag is established. When the third operating member  13  moves in the direction of arrow C 1 , a seventh shift stage is established, while, when the third operating member  13  moves in the direction of arrow C 2 , a fifth shift stage is established. When the fourth operating member  14  moves in the direction of arrow C 1 , a sixth shift stage is established, while, when the fourth operating member  14  moves in the direction of arrow C 2 , a reverse shift stage is established.  
      As is illustrated in  FIGS. 7 and 8 , the first operating member  11 , the second operating member  12 , the third operating member  13  and the fourth operating member  14  are respectively provided, thereon, with a first toothed portion  21 , a second toothed portion  22 , a third toothed portion  23  and a fourth toothed portion  24 , of which tooth phases in the shift direction are all matched together at the time that the operating members  11 ,  12 ,  13  and  14  are positioned at a neutral position (N). In details, the first toothed portion  21 , which is of rack-shaped and is integrally formed with parallel type teeth  21   c , extends in the sift direction on the first operating member  11 . The second toothed portion  22 , which is also of rack-shaped and is integrally formed with parallel type teeth  22   c , extends in the shift direction on the second operating member  12 . The third toothed portion  23 , which is also of rack-shaped and is integrally formed with parallel type teeth  23   c , extends in the shift direction on the third operating member  13 . The fourth toothed portion  24 , which is also of rack-shaped and is integrally formed with parallel type teeth  24   c , extends in the shift direction on the fourth operating member  14 .  
       FIG. 7  illustrates the operating members  11 - 14  which all are positioned at a neutral position N. The neutral position N is defined at an intermediate position in the shift direction of arrows C 1  and C  2 . When the operating members  11 - 14  are positioned at the neutral position N, tooth-shaped phases (tooth pitches) of the toothed portions  21 ,  22 ,  23  and  24  are all matched together among the operating members  11 - 14  in the shift direction. In other words, as illustrated in  FIGS. 4 and 5 , tooth tracess, of the respective teeth  21   c  of the first toothed portion  21  of the first operating member  11 , of the respective teeth  22   c  of the second toothed portion  22  of the second operating member  12 , of the respective teeth  23   c  of the third toothed portion  23  of the third operating member  13 , and of the respective teeth  24   c  of the fourth toothed portion  24  of the fourth operating member  24 , are formed in parallel all together. Moreover, at the neutral position (N), the tooth phases (tooth pitches), and the tooth shapes, of the respective operating members are all identical and matched together. According to the first embodiment of the present invention, the tooth phases (tooth pitches) of the respective operating members are all identical together with high precision on an assumption that industrial products on occasion may possess tolerance to a certain degree.  
      As is illustrated in  FIG. 3 , the switching engagement body  3  operates the first operating member  11 , the second operating member  12 , the third operating member  13  and the fourth operating member  14  in an independent manner therefrom, respectively. The switching engagement body  3  is mainly configured with the shift and select shaft  30  capable of being operated in the shift direction (illustrated with arrows C 1  and C 2 ) and in the select direction (illustrated with arrows S 1  and S 2 ), and an engagement gear  33  which is of pinion gear-shaped and is provided coaxially with the shift and select shaft  30  so as to rotate together with the shift and select shaft  30  in response to a shift operation of the shift and select shaft  30 . When the shift and select shaft  30  rotates about an axis P 1 , the engagement gear  33  rotates about the axis P 1  together with the shift and select shaft  30 . The engagement gear  33  is established with parallel-type plural teeth  33   c  thereon. Tooth traces of the teeth  33   c  of the engagement gear  33  are defined so as to be in parallel with the tooth traces of the teeth  21   c ,  22   c ,  23   c , and  24   c . Moreover, the tooth pitch of each toothed portion of the engagement gear  33  is substantially identical to the tooth pitch of each toothed portion  21 ,  22   23  and  24 , wherein each toothed portion of the engagement gear  33  is matched with each toothed portion  21 ,  22 ,  23  and  24 . The plural teeth  33   c  of the engagement gear  33  are therefore configured to be capable of being engaged with the toothed portions  21 ,  22 ,  23  and  24 .  
      As is illustrated in  FIG. 3 , the shift and select shaft  30  extends along the select direction (illustrated with arrows S 1  and S 2 ), and is provided with a rack gear  31  which also extends along the select direction.  
      The select actuator, which serves as a select operating means, is mainly configured with a select motor  52  incorporating, therein, a motor shaft  51  that rotates about an axis M 1 , and a pinion gear  53  which is formed on the motor shaft  51 . This pinion gear  53  can be engaged with the rack gear  31  of the shift and select shaft  30 . When the select motor  52  is driven, the pinion gear  53  rotates about the axis M 1  together with the motor shaft  51  rotating. In response to the rotation of the pinion gear  53 , the rack gear  31  moves in the select direction (illustrated with arrows S 1  and S 2 ), and the shift and select shaft  30  moves in this select direction together with the engagement gear  33 . Accordingly, the engagement gear  33  can face one of the first, second, third and fourth toothed portions  21 ,  22 ,  23  and  24 , and is engaged therewith.  
      The shift actuator, which serves as a shift operating means, is mainly configured with a shift motor  62  incorporating, therein, a motor shaft  61  that rotates about an axis M 2 , a pinion gear  63  which is established, thereon, with teeth  63   c , and is connected to the motor shaft  61  via a transmitting member  66 , and an oscillating body  64  which is established, thereon, with teeth  64   c , and oscillates in response to rotation of the pinion gear  63  in the shift direction (illustrated with arrows C 1  and C 2 ). This oscillating body  64  is connected to the shift and select shaft  30 . When the shift motor  62  of the shift actuator  6  is driven, the pinion gear  63  rotates, the oscillating body  64  is oscillated, and the shift and select shaft  30  then rotates in the shift direction (illustrated with arrows C 1  and C 2 ).  
      At the neutral position (N), the engagement gear  33  of the shift and select shaft  30  is engaged with a tooth  21   c  defined at an intermediate position in the shift direction of the first toothed portion  21  of the first operating member  11 . As is apparent from  FIGS. 4 and 5 , in order to establish a first shift stage from the neutral position (N), while the engagement gear  33  of the shift and select shaft  30  is being maintained at this current position illustrated in  FIG. 4 , the engagement gear  33 , which corresponds to a pinion gear, is rotated in a direction of arrow A 1  about the axis P 1 , wherein the first operating member  11  is moved, by a pinion and rack mechanism, in the shift direction of arrow C 1 . That is, when the engagement gear  33  of the shift and select shaft  30  is engaged with the first toothed portion  21  of the first operating member  11 , the first operating member  11  can be moved in the direction of arrow C 1 , wherein the first shift stage is established in the transmission.  
      On the other hand, at the neutral position (N) illustrated in  FIG. 4 , when a third shift stage is required, while the engagement gear  33  of the shift and select shaft  30  is being maintained at this current position illustrated in  FIG. 4 , the engagement gear  33  is rotated in a direction of arrow A 2  about the axis P 1 , wherein the first operating member  11  is moved, by a pinion and rack mechanism, in the shift direction of arrow C 2 . Accordingly, a third shift stage is established in the transmission.  
      When the first operating member  11  is moved from the neutral position (N) to a first shift stage position, a shift stroke SL, at which the first operating member  11  moves in the direction of arrow C 1 , is fundamentally designed at an amount corresponding to the number of teeth (an integer) which are employed for the shift operation. That is, the shift stroke SL is fundamentally designed at a distance of an integer of a whole thickness of teeth that are employed for the shift operation. Therefore, the shift stroke SL (unit: mm) is fundamentally designed at a distance calculated by multiplying the number of teeth (an integer), which are employed for the shift operation, by a tooth thickness of a single tooth. Therefore, upon a shift operation, the first operating member  11  moves at a distance that corresponds to the number of teeth (an integer) which is employed for the shift operation. On the other hand, when the first operating member  11  is moved from the neutral position (N) to a third shift stage position, a shift stroke SL, at which the first operating member  11  moves in the direction of arrow C 2 , is fundamentally designed at an amount corresponding to the number of teeth (an integer). Therefore, upon a shift operation to the third shift stage, the first operating member  11  moves at a distance that corresponds to an integral portion of the number of teeth.  
      According to the first embodiment of the present invention, even when any of the operating members is moved in the shift direction, tooth phases (tooth pitches) of the respective operating members can be effectively matched therewith. In consideration of errors, the shift stroke SL (unit: mm) can be designed at a distance (0.9-1.1) calculated by multiplying the number of teeth (an integer) by a tooth thickness of a single tooth.  
      Likewise, when the second operating member  12  is switched from the neutral position (N) to a fourth shift stage position, a shift stroke SL of the second operating member  12  in the direction of arrow C 1  corresponds to the number of teeth (an integer). When the second operating member  12  is switched from the neutral position (N) to a second shift stage position, a shift stroke SL of the second operating member  12  in the direction of arrow C 2  also corresponds to the number of teeth (an integer). Shift strokes SL of the third and fourth operating members  13  and  14  can be designed in the same manner.  
      Therefore, according to the first embodiment of the present invention, when the first operating member  11  is moved from a neutral position to a certain shift stage position, the first toothed portion  21  of the first operating member  11 , which has moved in the shift direction, can be matched, in terms of tooth phases (tooth pitches), with the toothed portions  22 ,  23  and  24  of the other operating members  12 ,  13  and  14 . Likewise, when the second operating member  12  is moved from the neutral position to a certain shift stage position, the toothed portion  22  of the second operating member  12 , which has moved in the shift direction, can be matched, in terms of tooth phases (tooth pitches), with the toothed portions  21 ,  23  and  24  of the other operating members  11 ,  13  and  14 . Further likewise, when the third operating member  13  is moved from the neutral position to a certain shift stage position, the toothed portion  23  of the third operating member  13  is matched, in terms of tooth phases (tooth pitches), with the other operating members  11 ,  12  and  14 . Still further, likewise, when the fourth operating member  14  is moved from the neutral position to a certain shift stage position, the toothed portion  24  of the fourth operating member  14  is matched, in terms of tooth phases (tooth pitches), with the toothed portions  21 ,  22  and  24  of the other operating members  11 ,  12  and  13 .  
      Next, described below is an operation at a shift operation from a first shift stage to a second shift stage with reference to  FIGS. 8 and 9 .  
      As is illustrated in  FIG. 8 , while the first operating member  11  is being positioned at a first shift stage position after movement in the direction of arrow C 1 , the shift and select shaft  30  is moved directly in a direction of arrow S 1 . As a result, the engagement gear  33  of the shift and select shaft  30  is released from being engaged with the first toothed portion  21  of the first operating member  11  and is engaged with the second toothed portion  22  of the second operating member  12 , as is illustrated in  FIG. 9 . As the reasons for that the above shift and select operation can be achieved, there are mainly three reasons: 1) the shift stroke SL from the neutral position (N) is designed at an amount corresponding to the number of teeth (an integer); 2) all of the toothed portions  21 ,  22 ,  23  and  24  are identical all together in terms of tooth phases (tooth pitches) and tooth shapes; and 3) all of the toothed portions  21 ,  22 ,  23  and  24  are matched all together in terms of tooth phases (tooth pitches) in the shift direction, i.e. in the direction of arrows C 1  and C 2 . Therefore, this structure facilitates an engagement switching operation of the engagement gear  33  from the first toothed portion  21  of the first operating member  11  to the second toothed portion  22  of the second operating member  12 . Further, according to the first embodiment of the present invention, the engagement gear  33  of the shift and select shaft  30  directly moves in the direction of arrow S 1 , it is not necessary for the engagement gear  33  to return to a neutral position, which is actually necessary according to a conventional work illustrated in  FIG. 14 . In such a case, in terms of a mechanical structure, a running distance of the engagement gear  33  can be abbreviated. Moreover, in terms of an operation, upon a select operation, only a single operation, by which the engagement gear  33  is moved directly in the direction of arrows S 1 , is required. Therefore, it is possible to abbreviate an operating time that is required.  
      Next, in response to activation of the shift actuator  6 , the shift and select shaft  30  and the engagement gear  33  are rotated, and the second operating member  12  is moved in the shift direction of arrow C 2 , as is illustrated in  FIG. 9 , wherein an actual shift stage is switched to a second shift stage.  
      In this case, as is illustrated in  FIG. 9 , while the first operating member  11  is being moved in the direction of arrow C 1 , the second operating member  12  is moved in the direction of arrow C 2 . In such circumstances, as far as the first clutch  201  and the second clutch  202  are both frictionally engaged with the clutch mating  550  and are connected to the crankshaft  520 , torque from the crankshaft  520  can be transmitted to the output shaft  305  not only via the first shift stage gear train  401  but also via the second shift stage gear train  402 . Therefore, according to the first embodiment of the present invention, it is possible to curb interrupting torque transmission from the crankshaft  520  to the output shaft  305 , and to perform torque transmission with high transmission efficiency. Moreover, it is possible to reduce a degree of unpleasant feeling that an occupant may have, and to reduce fuel consumption to an economic level. This results from the frictionally engagement disc-type clutches  201  and  203 . That is, even when torque transmission is implemented via the first clutch  201  and the second clutch  202 , the first clutch  201  and the second clutch  202  can slip.  
      When an actual shift stage has switched from the first shift stage to the second shift stage, the second clutch  202  is maintained to be frictionally engaged while the first clutch  201  is released from being frictionally engaged. In response to disengagement of the first clutch  201 , torque transmission path established to the output shaft  305  via the first drive gear  401  is interrupted. However, because the second clutch  202  is being frictionally engaged in this case, a torque transmission path is established to the output shaft  305  via the second shift stage gear train  402  of the second input shaft  302 .  
      Next, described below is an operation at a shift operation from a second shift stage to a third shift stage with reference to  FIGS. 9 and 10 .  
      As is illustrated in  FIGS. 9 and 10 , in response to activation of the select actuator  5 , the shift and select shaft  30  and the engagement gear  33  move directly in the direction of arrow S 2 . The engagement gear  33  of the shift and select shaft  30  can be easily switched from being engaged with the second toothed portion  22  of the second operating member  12  (see  FIG. 9 ) to being engaged with the first toothed portion  21  of the first operating member  11  (See  FIG. 10 ). Moreover, because the engagement gear  33  of the shift and select shaft  30  is moved directly in the direction of arrow S 2 , it is possible to abbreviate an operation time which is required to a select operation.  
      Next, described below is an operation for moving the shift and select shaft  30  in response to activation of the shift actuator  6 , and moving the first operating member  11  in the shift direction of arrow C 2 , wherein an actual shift stage is switched to a third shift stage.  
      In this case, as is illustrated in  FIG. 10 , while the second operating member  12  is being positioned at a second shift stage position after moving in the direction of arrow C 2 , the first operating member  11  is moved in the direction of arrow C 2 . In such circumstances, as far as the first clutch  201  and the second clutch  202  are both frictionally engaged with the clutch mating  550  and are connected to the crankshaft  520 , torque from the crankshaft  520  can be transmitted to the output shaft  305  not only via the first shift stage gear train  402  but also via the third shift stage gear grain  403 . Therefore, according to the first embodiment of the present invention, also when an actual shift stage is switched from a second shift stage to a third shift stage, it is possible to curb interrupting torque transmission from the crankshaft  520  to the output shaft  305 , and to perform torque transmission with high transmission efficiency. This results from the frictionally engagement disc-type clutches  201  and  203 . That is, even when torque transmission is implemented via the first clutch  201  and the second clutch  202 , the first clutch  201  and the second clutch  202  can slip.  
      When a shift operation from a third shift stage to a fourth shift stage is performed, or when a shift operation from a fourth shift stage to a fifth shift stage is performed, the same operation as described can be implemented.  
      As described above, according to the first embodiment of the present invention, it is possible to facilitate gear engagement of the engagement gear  33  of the shift and select shaft  30  among the toothed portions  21 ,  22 ,  23  and  24  of the operating members  11 - 14 . Further, upon a select operation, the engagement gear  33  of the shift and select shaft  30  is only moved directly in the direction of arrow S 2 , which is actually required by a conventional technology illustrated in  FIG. 4 . Therefore, according to the first embodiment of the present invention, there is no need for the engagement gear  33  to return to the neutral position, wherein it is possible to abbreviate an operating distance of the engagement gear  33 . Accordingly, a period of time, which is required for a shift and select operation, can be effectively abbreviated, and a shift response can be enhanced.  
      Next, described below is a shift operating apparatus according to a second embodiment of the present invention with reference to  FIGS. 11, 12  and  13 . The structure of the shift operating apparatus according to the second embodiment is basically the same as the structure of the apparatus according to the first embodiment, and the same effects can be generated. Therefore, as well as the first embodiment, gear engagement of the engagement gear  33  of the shift and select shaft  30  can be easily switched among the toothed portions  21 ,  22 ,  23  and  24  of the operating members  11 ,  12 ,  13  and  14 . Moreover, the engagement gear  33  of the shift and select shaft  30  can be only moved directly in the direction of either arrow S 1  or S 2 . Therefore, it is possible to abbreviate an operating distance of the engagement gear  33  and to shorten a period of time that is required for a shift operation of a vehicle.  
      Next, described is an only different structure of the second embodiment from the first embodiment. As is illustrated in  FIG. 11 , the switching engagement body  3  is mainly configured with the shift and select shaft  30 , the engagement gear  33 , which is formed at an axially intermediate portion of the shift and select shaft  30 , lock members  36  supported by the shift and select shaft  30 . The engagement gear  33  is rotatable about the axis P 1  of the shift and select shaft  30  relative to the shift and select shaft  30 . On the other hand, the lock members  36  are fixed to the shift and select shaft  30  by means of snap rings  37  so as not to drop out of the shift and select shaft  30 . Therefore, the engagement gear  33  is movable together with the shift and select shaft  30 .  
      The lock members  36  are positioned at both axial sides of the engagement gear  33 . The lock members  36  are of box-shaped and cover an outer periphery at an axially intermediate portion of the shift and select shaft  30 . On a surface of each lock member  36 , there is a lock toothed portion  38 , which has parallel-type teeth  38   c  and extends in parallel with the axis P 1  of the shift and select shaft  30 . Tooth phases (tooth pitches) of the teeth  38   c  of the lock toothed portion  38  are matched with tooth phases (tooth pitches) of the toothed portions  21 ,  22 ,  23  and  24  of the operating members  11 ,  12 ,  13  and  14 . Therefore, the lock members  36  can be engaged with the respective toothed portions  21 ,  22 ,  23  and  24  of the respective operating members  11 ,  12   13  and  14 . As a result, the lock members  36  can serve as a lock mechanism for locking the respective operating members  11 ,  12 ,  13  and  14  in place.  
      As is obvious from  FIG. 12 , while the engagement gear  33  of the shift and select shaft  30  is being engaged with the first toothed portion  21  of the first operating member  11 , the lock toothed portions  38  of the lock members  36  are engaged with toothed portions of operating members excluding the first operating member  11 , i.e., are engaged with the second toothed portion  22  of the second operating member  12 , the third toothed portion  23  of the third operating member  13 , the fourth toothed portion  24  of the fourth operating member  14 . Therefore, even when an outer force is applied to the group of operating members  1 , or to one of the operating members, it is possible to curb phase shift in the shift direction of either arrow C 1  or C 2 .  
      Therefore, when a shift stage is switched from a first shift stage to a second shift stage, it is possible to move the shift and select shaft  30  directly and reliably to the direction of arrow S 1  or S 2 . As described above, when the engagement gear  33  of the shift and select shaft  30  has been already engaged with the first toothed portion  21  of the first operating member  11 , the lock toothed portion  38  of the lock member  36  has been already engaged with the other toothed portions except for the first toothed portion  21  of the first operating member  11 , i.e., engaged with the second toothed portion  22  of the second operating member  12 , the third toothed portion  23  of the third operating member  13 , and the fourth toothed portion  24  of the fourth operating member  14 . Therefore, an only single operation is required to switch to a condition in which a shift operation can be implemented. That is, an unnecessary operation can be avoided.  
     Other Embodiments  
      The above-described embodiments are applied to a shift operating apparatus for a vehicle transmission that incorporates, therein, a plurality of clutches. However, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents that fall within the spirit and scope of the present invention as defined in the claims be embraced thereby.