Abstract:
A vehicular transmission, includes: an input shaft; a drive gear, fixed to the input shaft; an output shaft; a driven gear, brought in mesh with the drive gear, and provided at the output shaft; a hub configured to rotate along with the output shaft; a sleeve configured to rotate integrally with the hub, and configured to slide in an axial direction so as to connect the driven gear to the output shaft to drive; a parking gear, integrally formed with the sleeve; a claw member, provided at a vicinity of an outer periphery of the parking gear engageably with and disengageably from the parking gear; and a sleeve restricting member, provided with the claw member, and configured to restrict the sleeve from a movement in the axial direction when the claw member is moved in a direction of being engaged with the parking gear.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to a transmission for a vehicle including a parking gear. 
         [0003]    2. Description of the Related Art 
         [0004]    In an automatic transmission of a vehicle (automobile), there is a transmission referred to as a double clutch (also referred to as twin clutch or dual clutch) transmission for changing speed continuously while restraining a loss of a power by using a normal mesh type gear mechanism in which a drive gear and a driven gear are normally brought in mesh with each other. 
         [0005]    In a vehicle including an automatic transmission, inside of the transmission is provided with a parking gear and a claw member arranged at a vicinity of an outer periphery of the drive gear to be able to be engaged with and disengaged from the parking gear at inside of the transmission such that the vehicle is prevented from starting to move unpreparedly in a state of parking the vehicle and the vehicle is prevented from being moved unpreparedly in a parking state by engaging a front end of the claw member with the parking gear. 
         [0006]    In recent times, there is known a structure of integrating a parking gear between driven gears of an output shaft such that an excessive torque (caused by a vehicle weight when parked at an inclined location) is prevented from being operated to the parking gear. For example, as disclosed in JP-A-2006-52832, it is described that in a transmission constituting a forward speed changing stage by 6 stages, constituting a rearward speed changing stage by 1 stage, distributing three driven gears of 5 speed, 6 speed, reverse to a first output shaft, and distributing four driven gears of 1 speed, 2 speed, 3 speed, 4 speed to a second output shaft and providing a parking gear between the driven gears of the second output shaft, for example, between the driven gear of 3 speed and the driven gear of 4 speed. 
         [0007]    However, according to the transmission of the above-described example, in providing the parking gear at the output shaft, the parking gear is arranged at the output shaft in series with other gear, and therefore, there poses a problem that the output shaft is prolonged and an axial direction length of the transmission is prolonged. Hence, the inventors of the application have investigated to shorten the axial direction length by arranging the parking gear at a well-known synchronizer sleeve for connecting the driven gear to the output shaft to drive. Generally, the synchronizer sleeve is constituted so as not to move in the axial direction unless a constant or more of force is exerted in the axial direction by a well-known detent mechanism. However, when the parking gear is provided to the synchronizer sleeve, there is a rare case in which an operating force in engaging a claw member with the parking gear exceeds a restricting force by the detent mechanism from a positional relationship between the parking gear and the claw member and a behavior of the synchronizer sleeve becomes unstable. When the synchronizer sleeve is assumedly moved in the axial direction, also a position of the parking gear is moved and there is a concern that the engagement with the claw member becomes unstable. 
         [0008]    Further, in a vehicle of FF (front engine·front drive) type, a front portion of the vehicle is integrated with an engine, a transmission, a drive mechanism, a steering mechanism and the like, further, in a transversely placed engine, the engine is provided between tires, side members or the like, and therefore, there is a request that a length in the axial direction of the transmission is intended to be as short as possible. 
       SUMMARY 
       [0009]    It is therefore one advantageous aspect of the invention to provide a vehicular transmission capable of stably making a parking brake function while restraining a length in an axial direction thereof. 
         [0010]    According to an aspect of the invention, there is provided a vehicular transmission, including: an input shaft, configured to receive a drive force from a side of an engine; a drive gear, fixed to the input shaft, and configured to rotate along with the input shaft; an output shaft, provided in parallel with the input shaft; a bearing, configured to rotatably support a shaft end of the output shaft; a driven gear, brought in mesh with the drive gear, and provided pivotably at the output shaft; a hub, fixed to the output shaft contiguous to the driven gear on a side of the shaft end of the output shaft, and configured to rotate along with the output shaft; a sleeve, provided on an outer peripheral side of the hub, configured to rotate integrally with the hub, and configured to slide in an axial direction so as to connect the driven gear to the output shaft to drive; a parking gear, integrally formed with the sleeve; a claw member, provided at a vicinity of an outer periphery of the parking gear engageably with and disengageably from the parking gear; and a sleeve restricting member, provided with the claw member, and configured to restrict the sleeve from a movement in the axial direction when the claw member is moved in a direction of being engaged with the parking gear. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]    The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein: 
           [0012]      FIG. 1  is an outline view schematically showing a constitution of a vehicular transmission according to an embodiment of the invention; 
           [0013]      FIG. 2  is a sectional view showing a constitution of the vehicular transmission according to the embodiment of the invention; 
           [0014]      FIG. 3  is a sectional view viewing the transmission from an axial direction; 
           [0015]      FIG. 4  is an enlarged view showing a constitution of a sleeve restricting member; 
           [0016]      FIG. 5  is an enlarged view showing a constitution of a sleeve restricting member including a guide portion; and 
           [0017]      FIG. 6  is an enlarged view showing a state of restricting a sleeve by a sleeve restricting member. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0018]    An embodiment of a vehicular transmission according to the invention will be explained in reference to the drawings. 
         [0019]      FIG. 1  shows an outline constitution of a vehicular transmission. The vehicular transmission is a double clutch transmission of a transversely vehicle mounting type having speed changing stages of a total of 7 speeds of 6 speeds for a forward stage and 1 stage for a rearward stage. Notation  1  in the drawing designates a main body portion of the double clutch transmission, and the main body portion  1  is constituted by a structure of integrating an input mechanism  2  and an output mechanism  30 . 
         [0020]    The input mechanism  2  is constituted by a structure of integrating two of input shafts  9 ,  10  constituting a first and a second input shaft arranged with drive gears  3  through  7 , and two of clutches  12 ,  13  constituting a first and a second clutch. The output mechanism system  30  is constituted by including two of output shafts  40 ,  41  constituting a first and a second output shaft arranged with driven gears  31  through  37  and synchronizing mechanisms  50  through  53 . 
         [0021]    Next, the structure of the input mechanism  2  will be explained in reference to  FIG. 2  and  FIG. 3 .  FIG. 2  is a regular sectional view developing a double clutch transmission, and  FIG. 3  is a side sectional view of the double clutch transmission. In  FIG. 2 , notation  15  designates a clutch housing,  16  designates a transmission case connected in series with the clutch housing  15 , and the clutches  12 ,  13  are contained at inside of the clutch housing  15 . 
         [0022]    The clutches  12 ,  13  are aligned with, for example, two sets of pusher plates  12   a,    13   a  communicating with an output shaft of an engine  70  and two sets of independent dry type clutch plates  12   b,    13   b  respectively communicated with the input shafts  9 ,  10  alternately in an axial direction, and by moving (operating) the respective pusher plates  12   a,    13   a,  the respective pusher plates  12   a,    13   a  are made to function to be brought into close contact with and separated from the clutch plates  12   b,    13   b.    
         [0023]    Inside of the transmission case  16  is arranged with the input shafts  9 ,  10  substantially at a center thereof. The input shaft  9  is extended from a vicinity of an opening of the clutch housing  15  to a depth portion at inside of the transmission case  16 , that is, a vicinity of an end wall  16   a  on a side opposed to the clutches  12 ,  13 . The input shaft  9  is formed with a through hole  18  for passing a lubricant  67  (illustrated only in  FIG. 3 ) at an axis core. 
         [0024]    The input shaft  10  is constituted by a shape of a circular cylinder and integrated to an outer peripheral face of the input shaft  9  by way of a needle bearing  11  and the input shaft  9  and the input shaft  10  are made to be pivotable with each other by the needle bearing  11 . Notation  11   a  designates a through hole for guiding the lubricant  67  from the through hole  18  to the needle bearing  11 . 
         [0025]    The input shaft  10  is provided with a length of substantially a half of that of the input shaft  9  and covers an outer periphery of the input shaft  9  from one end side on a side of the clutches  12 ,  13  to substantially a center of inside of the transmission case  16 . A portion of double shafts including the input shaft  9  and the input shaft  10  is supported by a bearing  17   a  provided at a middle portion thereof. The bearing  17   a  is integrated to the end wall  16   b  partitioning the clutch housing  15  and the transmission case  16 . The input shaft  9  and the input shaft  10  are pivotably supported respectively by the bearing  17   a  and a bearing  17   b  mentioned above and the needle bearing  11  and made to be pivotable around respective axis centers. 
         [0026]    The end portion of the input shaft  9  projected into the clutch housing  15  is connected to the clutch  13 , specifically, the clutch plate  13   b  of the clutch  13 , similarly, the end portion of the input shaft  10  is connected to the clutch plate  12   b  of the clutch  12 . Further, when the clutch  13  is connected, a rotational force outputted from the engine  70  is transmitted to the input shaft  9  and when the clutch  12  is connected, the rotational force outputted from the engine  70  is transmitted to the input shaft  10 . That is, by operating the clutches  12 ,  13 , the rotational force of the engine  70  is transmitted selectively to either one of the input shaft  9  and the input shaft  10 . 
         [0027]    The input shafts  9 ,  10  are provided with the drive gears  3  through  7 . Specifically, the forward speed change stage (1 through 6 speed) including the drive gears  3  through  7  is divided into two speed change stage groups, that is, speed change stage groups of even number speed change stages and odd number speed change stages, and the drive gears  3  through  5  in correspondence with the odd number speed change stage group are provided at the input shaft  9 . 
         [0028]    Specifically, a shaft portion  9   a  projected from the input shaft  10  (input shaft  9 ) is provided with the drive gear  3  for 1 speed, the drive gear  4  for 3 speed, the drive gear  5  for 5 speed in this order from a point (rear end side of transmission) contiguous to the bearing  17   b.  Particularly, the drive gear  3  for 1 speed is made to increase a speed reduction ratio by using a structure of forming meshing teeth directly on an outer peripheral face of the shaft portion  9   a  by a tool without forming a hub portion in a shape of a circular disk at the shaft portion  9   a  without forming the meshing teeth at the hub portion by a tool as in other drive gears  4 ,  5  for 3 speed or for 5 speed. Further, at the drive gear contiguous to the drive gear  3  for 1 speed, a next gear on a low speed side, that is, the drive gear  4  for 3 speed is arranged, and in forming the drive gear  3  for 1 speed, an interference with the tool is avoided by a short distance and an increase in a distance between the drive gears is restrained. 
         [0029]    The drive gears in correspondence with the even number speed change stage group are provided at the input shaft  10 . Specifically, the input shaft  10  is provided with the drive gear  6  for both of 4 speed and 6 speed, the drive gear  7  for 2 speed in this order from an end portion on a rear end side of the transmission. Thereby, when the clutch  13  is connected, the rotational force of the engine  70  is transmitted to the drive gears  3  through  5  of odd number stages and when the clutch  12  is connected, the rotational force of the engine  70  is transmitted to the drive gears  6  and  7  of the even number stages. 
         [0030]    Next, the output mechanism  30  will be explained in reference to  FIG. 2  and  FIG. 3 . Both of the output shafts  40 ,  41  constituting the output mechanism  30  are arranged in parallel with the input shafts  9 ,  10  at inside of the transmission case  16 . The output shaft  40  is arranged on an upper side of the input shafts  9 ,  10  (input shaft portion) of a double structure and the output shaft  41  is arranged on a lower side of the input shafts  9 ,  10 . 
         [0031]    Both of the output shafts  40 ,  41  are arranged by aligning end portions on sides of the clutches  12 ,  13  at a position of the end wall  16   b.  The respective aligned shaft ends of the output shafts  40 ,  41  are pivotably supported by respective bearings  38   a,    38   b  integrated to the end wall  16   b  Further, shaft ends constituting a transmission rear end side of the output shafts  40 ,  41  are pivotably supported by respective bearings  39   a,    39   b  integrated to the end wall  16   a.    
         [0032]    End portions on sides of the clutches  12 ,  13  of the output shafts  40 ,  41  are respectively provided with output gears  42 ,  43 , and the output gears  42 ,  43  are brought in mesh with a differential mechanism  44  integrated to a side portion of the transmission case  16  as shown by  FIG. 3 . 
         [0033]    The differential mechanism  44  is constituted by a differential gear portion  44   e  formed by a combination of respective elements, specifically, pinion gears  45   a  through  45   d,  a ring gear  46  (reduction gear) for inputting rotation to the differential gear portion  44   e,  axles  47   a,    47   b  for transmitting the rotational force distributed by the differential gear portion  44   e  to left and right drive wheels (not illustrated) at inside of an outer wall  45  formed by a side portion of the transmission case  16 . The left and right gears  42 ,  43  are brought in mesh with the ring gear  46  of the differential mechanism  44 . Further, a speed reduction ratio of the output gears  42 ,  43  may be set such that a final speed reduction ratio of the output shaft  40  becomes larger than a final speed reduction ratio of the output shaft  41 . 
         [0034]    The output shaft  40  is arranged with the three driven gears in an order of the driven gear  31  for 5 speed brought in mesh with the drive gear  5 , the driven gear  32  for 4 speed brought in mesh with the drive gear  6 , the driven gear  33  for reverse from a side of the bearing  39   a.  The output shaft  41  is arranged with the four driven gears in an order of the driven gear  34  for 1 speed brought in mesh with the drive gear  3 , the driven gear  35  for 3 speed brought in mesh with the drive gear  4 , the driven gear  36  for 6 speed brought in mesh with the drive gear  6 , the driven gear  37  for 2 speed brought in mesh with the drive gear  7  from a side of a bearing  39   b.  The output shafts  40 ,  41  are distributed with the driven gears  31  through  36  such that a number of speed change stages of the output shaft  40  becomes smaller than a number of speed change stages of the output shaft  41 . 
         [0035]    Here, in the gears, both of tooth width dimensions α 1 , α 2  of the drive gears  3 ,  7  (1 speed, 2 speed) of low speed stage gears arranged contiguous to the bearings  17   a,    17   b  are made to be larger than tooth width dimensions β 1 , β 2  of the driven gears  34 ,  37  brought in mesh therewith. Further, only the driven gears  34 ,  37  brought in mesh with the drive gears  3 ,  7  having wide width are brought in mesh therewith in a state of being made to be proximate to one sides in a width direction. The driven gears  31  through  37  are rotatably supported by outer peripheral faces of the output shafts  40 ,  41  by using needle bearings  48  all of which constitute bearing portions. 
         [0036]    Synchronizing mechanisms  50  through  53  are distributed in accordance with a layout of the driven gears  31  through  37  (layout making a speed change stage number on the side of the output shaft  40  smaller than that on the side of the output shaft  41 ), and provided at the output shafts  40 ,  41 . Specifically, a shaft portion of the output shaft  40  between the driven gear  32  (for 4 speed) and the driven  33  (for reverse) is arranged with the synchronizing mechanism  50  for selecting 4 speed and reverse of two direction types in shift directions, and a shaft portion thereof on a side of the bearing  39   a  interposing the driven gear  31  (for 5 speed) is arranged with the synchronizing mechanism  51  for selecting 5 speed of one direction type in a shift direction. 
         [0037]    Further, a shaft portion of the output shaft  41  between the driven gear  34  (for 1 speed) and the driven gear  35  (for 3 speed) is arranged with the synchronizing mechanism  52  for selecting 1 speed and 3 speed of two direction type in shift direction, and a shaft portion thereof between the driven gear  36  (for 6 speed) and the driven gear  37  (for 2 speed) is arranged with the synchronizing mechanism  53  for selecting 6 speed and 2 speed of two direction type in shift direction. By aligning the respective gears and the respective synchronizing mechanisms in this way, the end portion of the output shaft  40  on the upper side is escaped to the side of the clutches  12 ,  13  by a difference of the speed change stage number relative to the output shaft  41  on the lower side. That is, a total length of the output shaft  40  becomes shorter than that of the output shaft  41 . 
         [0038]    There is used a structure in which all of the synchronizing mechanisms  50 ,  52 ,  53  in two direction type are fitted with synchronizer hubs  55  by splines, an outer peripheral portion of the synchronizer hub  55  is integrated with a synchronizer sleeve  56  as a sleeve slidably in an axial direction, respective gears arranged on both sides of the synchronizer hubs  55  are respectively formed with synchronizer cones  57  and synchronizer rings  58  are fitted to be inserted respectively to cone faces of outer peripheries of the synchronizer cones  57 . Further, the notations are illustrated at the synchronizing mechanism  50 ,  52 . 
         [0039]    Thereby, in the respective synchronizing mechanism  50 ,  52 ,  53 , when the synchronizer sleeves  56  are slid in either direction in the axial direction, by friction of the synchronizer ring  58  and the synchronizer cone  57 , while reducing a rotational speed difference, the output shaft  40  or the output shaft  41  and the driven gears of the respective speed change stages are engaged (synchronizing mesh) and the both members are integrally rotated. The synchronizer sleeve  56  is constituted not to move in the axial direction unless a constant or more of force is exerted in the axial direction by a well-known detent mechanism, not illustrated. 
         [0040]    Here, the synchronizing mechanism  52  integrated to the driven gear  34  (for 1 speed) is larger than an outer diameter of the synchronizer sleeve  56  in a gear diameter thereof and is arranged as proximate to the driven gear  34  as possible. A structure of making proximate thereto is constituted such that a recess portion  55   a  in a ring-like shape is formed around an axis center over a total of a side face on a side of the synchronizing mechanism  52  of the driven gear  34 , inside of the recess portion  55   a  is provided with the synchronizer ring  58 , the synchronizer cone  57 , and a portion of the sliding synchronizer sleeve  56  is brought to inside of the recess portion  55   a.  That is, the synchronizer sleeve  56  of the synchronizing mechanism  52  completes synchronizing mesh at a position brought from a side face to an inner side of the driven gear  34  (for 1 speed) more than other speed change stage and a distance from the driven gear  34  to the synchronizer hub  55  is made to be short by that amount. 
         [0041]    The synchronizing mechanism  51  of one direction type is constituted by a structure the same as the structure in which the synchronizer cone  57 , the synchronizer ring  58  on one side of the synchronizing mechanisms  50 ,  52  of two direction type is omitted, and a shift direction is constituted only by one direction of being remote from the bearing  39   a.  That is, when the synchronizer sleeve  56  is slid to the driven gear  31 , while reducing the rotation speed difference by friction, the output shaft  40  and the driven gear  31  for 5 speed are engaged. 
         [0042]    Further, a side portion of the driven gear  37  (for 2 speed) on a side opposed to a side of the synchronizing mechanism  53  is coaxially attached with an idler gear  60  for reverse. The idler gear  60  is smaller than the driven gear  37  in a gear diameter thereof, brought in mesh with the driven gear  33  for reverse of the output shaft  40 , and when the driven gear  33  for reverse is engaged with the output shaft  40  by the synchronizing mechanism  50 , an output of a reverse rotation a speed of which is reduced by speed reduction ratio of 2 speed speed change stage, a speed reduction ratio of reverse speed change stage, further, a final speed reduction ratio of the output shaft  40  and is transmitted to the differential mechanism  44 . 
         [0043]    Further, an end portion (escaped end portion) of the output shaft  40  on the side of the rear end of the transmission is provided with a parking gear  61  as shown by  FIG. 2 . The synchronizer sleeve  56  of the synchronizing mechanism  51  is extended to a side of the bearing  39   a,  and the parking gear  61  is provided at the extended synchronizer sleeve  56  integrally with an extended outer peripheral face thereof. That is, the parking gear  61  is formed integrally with the synchronizer sleeve  56  moved to a side of the synchronizer cone  57  when the synchronizing mechanism  51  is operated. 
         [0044]    The synchronizer hub  55  is extended to a side of the bearing  39   a  similar to the synchronizer sleeve  56 , an inner diameter of a shaft end side of the synchronizer hub  55  is formed to be larger than an outer diameter of the bearing  39   a  and a portion of a shaft end side of the synchronizer hub  55  is provided to overlap an outer side of the bearing  39   a  (overlapped). 
         [0045]    As shown by  FIG. 3 , a vicinity of an outer periphery of the parking gear  61  is provided with a claw member  62  for locking integrated to the transmission case  16  engageably and disengageably with and from the parking gear  61 , and when the gear is set to parking by operating a shift control lever, not illustrated, the claw member  62  is engaged with the parking gear  61 , and the output shaft  40  is locked. By locking the output shaft  40 , the axle  47   a  and the axle  47   b  are locked. 
         [0046]    By attaching the parking gear  61  in this way, as shown by  FIG. 2 , there is constructed a constitution in which a side portion of an upper stage of the main body portion  1  can be escaped, that is, can be constituted by a shape of restraining an extrusion on the rear end side of the transmission more than other portion, when the double clutch transmission is mounted transversely at an engine room (not illustrated) of a vehicle, an interference with the skeleton member of a vehicle body, for example, a side frame  63  can be avoided. 
         [0047]    As shown by  FIG. 3 ,  FIG. 4 , the claw member  62  is provided with a sleeve restricting member  80  for rectifying a movement of the synchronizer sleeve  56  in the axial direction when the claw member  62  is moved in a direction of being engaged with the parking gear  61 . The sleeve restricting member  80  is made of a sheet metal and a shape of a total thereof constitutes an L-like shape in a section thereof. Other end  80   b  of the sleeve restricting member  80  is fixed to an upper face  62   b  of the claw member  62  made of a metal by welding such that one end  80   a  thereof is disposed on a side of the parking gear  61 . Although the fixing method may be constituted not by welding but by fastening using a bolt or the like, a space at inside of the transmission case  16  is narrow and in consideration of a positional shift or the like by loosening, it is preferable to fix by welding. 
         [0048]    The sleeve restricting member  80  is constructed by a constitution in which in a state of being fixed to the claw member  62 , the one end  80   a  is formed to project to a side of the parking gear  61  more than a front end  62   a  of the claw member  62  engaged with the parking gear  61 , and inserted to be engaged with a shift fork groove  83  formed at the synchronizer sleeve  56 . 
         [0049]    An operation of connecting and disconnecting the respective clutches  12 ,  13  (pusher plates  12   a,    13   a ) or an operation of shifting to select the respective synchronizing mechanisms  50  through  53  is carried out by an actuator controlled by, for example, an instruction of ECU (both of which are not illustrated). Further, the double clutch transmission carries out automatic transmission in accordance with speed change information set by ECU while minimizing a loss of cutting power transmission. 
         [0050]    Next, an operation of the double clutch transmission will be explained. In setting 1 speed, first, by the actuator operated by a speed change instruction outputted from ECU, the synchronizer sleeve  56  of the synchronizing mechanism  52  of the odd number speed change stage group is slid to a side of 1 speed to engage the driven gear  34  for 1 speed and the output shaft  41 . Thereby, the speed change stage of 1 speed is selected. Thereafter, the clutch  13  is operated to connect by the actuator similarly operated by the speed change instruction. By connecting the clutch  13 , shift of 1 speed is finished. Thereby, the output of the engine  70  is changed in the speed by a transmission line of odd number route transmitted to the input shaft  9 , the drive gear  3  for 1 speed, the driven gear  34  for 1 speed, the output shaft  41 . Further, a rotational output the speed of which is changed is transmitted from the output shaft  43  to the differential mechanism  44 , transmitted to the left and right axles  47   a,    47   b,  and the vehicle is run by 1 speed. Further, in such a state, the clutch  12  is brought into a disconnected state. 
         [0051]    When an instruction of changing speed to 2 speed is outputted in running by 1 speed, since although the clutch  13  is connected, the clutch  12  is brought into the disconnected state, the synchronizer sleeve  56  of the synchronizing mechanism  53  of the even number speed change group is slid to a side of 2 speed beforehand, and the driven gear  37  for 2 speed can be engaged with the output shaft  41  rotated at a current vehicle speed. Thereby, the drive gear  7  of 2 speed speed change stage constituting next stage is synchronized with the vehicle speed and the speed change stage of 2 speed is selected. That is, speed change to next stage is prepared. 
         [0052]    Thereafter, by releasing connection of the clutch  13 , connection of the clutch  12  is carried out, and power transmission from the engine  70  is switched from the input shaft  9  to the input shaft  10 . Then, the speed of the output of the engine  70  is changed by a transmission line of even number route transmitted to the input shaft  10 , the drive gear  7  for 2 speed, the driven gear  37  for 2 speed, the output shaft  40 , and the speed changing rotation is outputted from the output gear  43  to the differential mechanism  44  (2 speed shift finish). By switching to 2 speed, the vehicle is promptly switched to 2 speed running. 
         [0053]    When a speed change instruction to 3 speed is outputted in running at 2 speed, in a state of connecting the clutch  12 , the clutch  13  is brought into the disconnected state, and therefore, the synchronizer sleeve  56  of the synchronizing mechanism  52  of the odd number speed change group is slid to 3 speed side beforehand, and the driven gear  35  for 3 speed can be engaged with the output shaft  40  rotated at the current vehicle speed. Thereby, the speed change stage of 3 speed is selected by synchronizing the drive gear  4  of 3 speed speed change stage constituting a next stage with the output shaft  40 . Thereby, the drive gear  4  of 3 speed speed change stage constituting the next stage is synchronized with the vehicle speed and the speed change stage of 3 speed is selected. That is, the speed change to the next stage is prepared. Thereafter, while releasing connection of the clutch  12 , connection of the clutch  13  is carried out, the transmission of the engine  70  is switched again from the input shaft  10  to the input shaft  9 . Then, the speed of the output from the engine  70  is changed by the transmission line of the odd number route transmitting to the input shaft  9 , the drive gear  4  for 3 speed, the driven gear  35  for 3 speed, the output shaft  41 , and the speed changing rotational output is transmitted from the output gear  43  to the differential mechanism  44  (3 speed shift finish). By switching to 3 speed, the vehicle is promptly switched to 3 speed running. 
         [0054]    Further, by alternately switching the clutches  12 ,  13  by alternately selecting the speed change stage by the odd number speed change group, the even number speed change group similar to the above-described by the synchronizing mechanisms  50 ,  51 ,  53  end the clutches  12 ,  13 , in shifting remaining speed change stages of 4 speed, 5 speed, 6 speed, similar to the above-described speed change operation of 1 through 3 speed, the speed is changed continuously and swiftly while minimizing the transmission loss. 
         [0055]    Further, in changing speed to the reverse speed change stage, the driven gear  33  for reverse and the output shaft  40  are engaged by sliding the synchronizer sleeve  56  of the synchronizing mechanism  50  to the reverse speed side from a state of disconnecting the clutches  12 ,  13 . Thereby, the speed change stage of reverse speed is selected. Thereafter, the clutch  12  is disconnected. Thereby, the output from the engine  70  is transmitted to the differential mechanism  44  by way of the input shaft  10 , the drive gear  7  for 2 speed, the driven gear  37  for 2 speed, the idler gear  60  attached to the driven gear, the driven gear  33  for reverse, the output shaft  40 , the output gear  42 . That is, rotation of the output shaft  40  is transmitted to the differential mechanism  44  by constituting an output of reverse rotation the speed of which is reduced by a speed reduction ratio of 2 speed speed change stage, a speed reduction ratio of reverse speed change stage, further, the final speed reduction ratio of the output shaft  41  and the vehicle is reversed by the large speed reduction ratio. 
         [0056]    As shown by  FIG. 3 , parking lock is carried out by pivoting (moving) the claw member  62  to the engaging side by operating the actuator cooperatively moved by parking operation and engaging the claw portion  62   a  of the front end of the claw member  62  with a tooth portion  61   a  (illustrated only in  FIG. 3 ) of the outer periphery of the parking gear  61 . By the engagement, the output shaft  40  is locked, and the vehicle is constrained not to move. At this occasion, the synchronizer sleeve  56  is not operated but normally returns to the left side of the drawing. 
         [0057]    In this way, the parking gear  61  is provided integrally with the synchronizing mechanist  51  (for 5 speed) arranged at the end of the output shaft  40  and the most proximate to the shaft end at which a mesh number of the speed change stage is small, and therefore, the parking gear  61  can be provided at the output shaft  40  easily without changing the layout of the driven gears  31  through  33  (for 5 speed, for 4 speed, for reverse) on the output shaft  40  and the synchronizing mechanisms  51 ,  50  (for 5 speed, for 4 speed, for reverse) 
         [0058]    Further, it is not necessary to directly provide the parking gear  61  at the output shaft  40 , and therefore, a number of parts can be reduced, an integrating step can be simplified, an outer shape of the main body portion  1  of the double clutch transmission, that is, a maximum dimension in the axial direction of the transmission case  16  can be narrowed. Further, by constructing a constitution of arranging the output shaft  40  attached with the parking gear  61  and having a small number of speed change stages on the upper side and arranging the output shaft  41  having a large number of speed change stages on the lower side, as shown by  FIG. 3 , the large recess shape la escaping from the side frame  63  (skeleton member arranged in a vehicle width direction of vehicle body) of the engine room opposed to the upper stage side portion is ensured at the upper stage side portion of the main body portion  1  in being mounted to the vehicle (transversely), and therefore, a sufficient transverse mounting function can be ensured and mountability of the double clutch transmission can be promoted. 
         [0059]    Particularly, the parking gear  61  is attached to the synchronizing mechanism  51  constituting shift direction by one direction, and therefore, one side of the synchronizing mechanism  51  which has not been used in the background art can effectively be utilized and a dead space at inside for transmission can be reduced. Further, the parking gear  61  can be provided at the outer periphery of the bearing  39   a  to overlap each other in the axial direction (overlapped), further small-sized formation can be carried out. Further, the synchronizer hub  55  is extended in the axial direction, and therefore, a holding portion is prolonged and the parking gear  61  can firmly be held. Further, the parking gear  61  can be installed by integrating the synchronizer sleeve  56  (synchronizing mechanism  51 ) to the output shaft  40  and an integrating step can considerably be simplified. 
         [0060]    There is a rare case in which when, for example, the vehicle body is inclined in pivoting (moving) the claw member  62  to the engaging side, from a positional relationship of the parking gear  61  and the claw member  62 , an operating force in engaging the claw member  62  to the parking gear  61  exceeds the restricting force by the detent mechanism and there is a case in which the synchronizer sleeve  56  is moved in the axial direction by an amount of rattle thereof. However, according to the embodiment, there is provided the sleeve restricting member  80  for rectifying the movement of the synchronizer sleeve  56  in the axial direction when the claw member  62  is moved in the direction of engaging with the parking gear  61  at the claw member  62  arranged at the vicinity of the outer periphery of the parking gear  61  engageably with and disengageably front the parking gear  61 , and therefore, even when an excessively large force is operated to the parking gear  61  when the claw member  62  is engaged with the parking gear  61 , the movement in the axial direction can be restricted by inserting the one end  80   a  of the sleeve restricting member  80  to the shift fork groove  83 . Therefore, the positional relationship of the parking gear  61  and the claw member  62  is stabilized, the parking brake can stably be functioned. 
         [0061]    Further, the one end  80   a  of the sleeve restricting member  80  is formed to project to the side of the parking gear  61  more than the claw portion  62   a  of the front end of the claw member  62  engaged with the parking gear  61 , and therefore, before the parking gear  61  and the claw member  62  are engaged, the one end  80   a  of the sleeve restricting member  80  is engaged with the shift fork groove  83  of the synchronizer sleeve  56 , and therefore, the movement of the synchronizer sleeve  56  in the axial direction can further firmly be rectified and the parking brake can further stably be functioned. 
         [0062]    The sleeve restricting member  80  is made of a sheet metal, and therefore, a rigidity thereof can be ensured while achieving thin light-weighted formation, the movement of the synchronizer sleeve  56  in the axial direction is rectified by saving a space and the parking brake can further stably be functioned. 
         [0063]    Although according to the embodiment, the sleeve restricting member  80  is constituted by substantially the same plate thickness and the one end  80   a  is constituted to be inserted to the shift fork groove  83 , as shown by  FIG. 5 , the side of the one end  80   a  inserted to the shift fork groove  83  may be formed to be thick in the axial direction, and an inclined guide portion  84  of pressing the parking gear  61  in the shift fork groove  83  in the axial direction may be formed. That is, the guide portion  84  for moving the parking gear  61  to the position of engaging with the claw member  62  may be formed at the sleeve restricting member  80 . The guide portion  84  moves the synchronizer sleeve  56  (parking gear  61 ) by being brought into contact with an edge portion  83   b  of the shift fork groove  83  when the claw member  62  is moved in the engaging direction and the one end  80   a  is inserted to inside of the shift fork groove  83 . The synchronizer sleeve  56  is constituted not to move in the axial direction unless the constant or more of force is exerted in the axial direction by the detent mechanism, not illustrated, and therefore, when the side of the one end  80   a  of the sleeve restricting member  80  is inserted to inside of the shift fork groove  83 , as shown by  FIG. 6 , an inner face  80   c  of the sleeve restricting member  80  continuous from the guide portion  84  is brought into contact with an inner side face  83   a  of the shift fork groove  83 , and therefore, the movement in the axial direction is restricted. 
         [0064]    By providing the guide portion  84  at the sleeve restricting member  80 , when the parking gear  61  and the claw member  62  are engaged, the synchronizer sleeve  56  is moved to the engaging position by the guide portion  84 , and therefore, the engagement of the parking gear  61  and the claw member  62  is ensured and the parking brake can further stably be functioned. Further, even in a case in which when the sleeve  56  is returned from 5 speed shift state to a neutral position, the sleeve  56  cannot be returned since the restricting force or the detent mechanism is weak and the position of the sleeve  56  is shifted, the engagement of the parking gear  61  and the claw member  62  is further ensured by the guide groove  84 , and the parking brake can further stably be functioned. 
         [0065]    Further, the invention is not limited to the above-described one embodiment but may be embodied by being variously changed within the range not deviated from the gist of the invention. For example, although according to the one embodiment, the example of providing the synchronizing mechanism  51  most proximately to the escaped other end portion of the output shaft  40  is pointed out, the invention is not limited thereto but is applicable in a case of arranging the driven gear  31  most proximately to other end portion by switching positions of the synchronizing mechanism  51  and the driven gear  31  of 5 speed. 
         [0066]    The invention thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.