Abstract:
A drive force transmitting apparatus for a vehicle including a drive source, a drive force transmitting path adapted to be connected to a drive shaft to transmit a drive force from the drive source to the drive shaft, and a clutch mechanism capable of connecting and disconnecting the drive force transmitting path. The drive force transmitting apparatus further includes a parking mechanism provided in the drive force transmitting path and capable of stopping the rotation of the drive shaft and an actuator mechanism capable of selectively operating the clutch mechanism and the parking mechanism.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a drive force transmitting apparatus for a vehicle including a drive force connecting and disconnecting mechanism (clutch mechanism) and a parking mechanism. 
     2. Description of the Related Art 
     A parking lock apparatus in a vehicle having a continuously variable transmission (CVT) is disclosed in Japanese Patent Laid-open No. Sho 59-222668. The parking lock apparatus disclosed in this publication is provided in an auxiliary transmission added to the CVT. This auxiliary transmission includes an input shaft, an output shaft, and an intermediate shaft (reverse idler shaft) and further includes a parking shaft extending parallel to each shaft mentioned above and nonrotatably mounted to a transmission case. 
     A parking gear is nonrotatably mounted on this parking shaft. A reverse driven gear is axially slidably provided on the output shaft. In effecting a parking lock condition, the reverse driven gear is selectively engaged with the parking gear to thereby lock the transmission. In the parking lock apparatus disclosed in Japanese Patent Laid-open No. sho 59-222668, however, the parking shaft for mounting the parking gear must be specially added, causing an increase in size of the transmission case and further causing a great increase in total weight of the transmission. 
     A parking lock apparatus in a parallel axes type transmission is disclosed in Japanese Patent Laid-open No. 2001-50392. The parking lock apparatus disclosed in this publication includes a lock gear adapted to be selectively engaged with a reverse idle gear provided in a transmission case. The reverse idle gear is movable among a neutral position, a reverse position where the reverse idle gear meshes with a main shaft reverse gear and a counter shaft reverse gear, and a parking position where the reverse idle gear meshes with at least the main shaft reverse gear and the lock gear. In the parking lock apparatus disclosed in Japanese Patent Laid-open No. 2001-50392, however, a reverse mechanism and a parking mechanism are commonly used. Accordingly, this parking lock apparatus cannot be applied to a hybrid vehicle or the like such that a motor is used for reverse running. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of the present invention to provide a drive force transmitting apparatus for a vehicle having an actuator mechanism capable of selectively operating a clutch mechanism and a parking mechanism. 
     In accordance with an aspect of the present invention, there is provided a drive force transmitting apparatus for a vehicle including: a drive source; a drive force transmitting path adapted to be connected to a drive shaft to transmit a drive force from the drive source to the drive shaft; a clutch mechanism capable of connecting and disconnecting the drive force transmitting path; a parking mechanism provided in the drive force transmitting path and capable of stopping the rotation of the drive shaft; and an actuator mechanism capable of selectively operating the clutch mechanism and the parking mechanism. 
     With this arrangement, the drive force transmitting apparatus includes the actuator mechanism capable of selectively operating the clutch mechanism and the parking mechanism. Accordingly, as compared with the case that any dedicated selector apparatus is provided for each mechanism, the number of parts can be greatly reduced to thereby greatly reduce the cost and weight of the drive force transmitting apparatus. 
     Preferably, the actuator mechanism can switch among a first condition where the clutch mechanism is engaged to connect the drive force transmitting path, and the parking mechanism is disengaged to cancel a parking lock condition where the drive shaft is fixed in rotation; a second condition where the clutch mechanism is disengaged to disconnect the drive force transmitting path, and the parking mechanism is disengaged to cancel the parking lock condition; and a third condition where the clutch mechanism is disengaged to disconnect the drive force transmitting path, and the parking mechanism is engaged to effect the parking lock condition. 
     Accordingly, in the case that the parking mechanism is engaged to effect the lock condition of the vehicle, the clutch mechanism is always kept in its disengaged condition. Conversely, in the case that the clutch mechanism is engaged to effect the on-line condition where the drive source is connected to the drive shaft, the parking mechanism is always kept in its disengaged condition. Accordingly, it is possible to prevent a malfunction such that the parking mechanism is engaged during running by the drive source. 
     Preferably, the actuator mechanism includes a rotating shaft to which a cam portion and a parking pivot portion are fixed, means for pivotally rotating the rotating shaft, and an operating fork adapted to be moved by the cam portion for operating the clutch mechanism; the clutch mechanism is selectively engaged by pivotally rotating the cam portion together with the rotating shaft to thereby move the operating fork; and the parking mechanism includes a parking pawl adapted to be pivotally rotated by pivotally rotating the parking pivot portion together with the rotating shaft and a parking gear fixed to the drive shaft, the parking pawl being engageable with the parking gear. 
     More preferably, the cam portion includes a one-way cam mechanism adapted to move the operating fork in the case of switching between the second condition and the first condition and not to move the operating fork in the case of switching between the second condition and the third condition. 
     The above and other objects, features and advantages of the present invention and the manner of realizing them will become more apparent, and the invention itself will best be understood from a study of the following description and appended claims with reference to the attached drawings showing some preferred embodiments of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a skeleton diagram of a drive force transmitting apparatus according to a preferred embodiment of the present invention; 
         FIG. 2  is a perspective view of an actuator mechanism according to the preferred embodiment of the present invention; 
         FIG. 3  is an elevational view of the actuator mechanism; 
         FIG. 4  is a perspective view of the actuator mechanism as viewed from the back side; 
         FIGS. 5A to 5C  are schematic plan views for illustrating the operation of a one-way cam, specifically  FIG. 5A  includes in the actuator mechanism in the case of engaging a clutch mechanism,  FIG. 5B  is a view similar to  FIG. 5A , showing a neutral condition, and  FIG. 5C  is a view similar to  FIG. 5A , showing the case of performing a parking lock operation. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIG. 1  is a skeleton diagram of a drive force transmitting apparatus for a hybrid vehicle according to a preferred embodiment of the present invention. A crankshaft  4  of an engine  2  is connected to a clutch  6 . A drive force generated by the engine  2  is input to a main shaft (input shaft)  10  of a transmission  8  by engaging the clutch  6 . The configuration of the clutch  6  may be of such a type that it is manually disengaged by depressing a clutch pedal or automatically disengaged by an actuator. The main shaft  10  of the transmission  8  is rotatably supported by a pair of bearings  12  and  14 . A counter shaft (output shaft)  16  extending parallel to the main shaft  10  is also rotatably supported by a pair of bearings  18  and  20 . 
     There are provided on the main shaft  10  a first speed drive gear  22 , a reverse drive gear  24 , a second speed drive gear  26 , a third speed drive gear  28 , a 3-4 speed synchromesh mechanism  36 , a fourth speed drive gear  30 , a fifth speed drive gear  32 , a 5-6 speed synchromesh mechanism  38 , and a sixth speed drive gear  34 . These elements  22 ,  24 ,  26 ,  28 ,  36 ,  30 ,  32 ,  38 , and  34  are arranged in this order in the axial direction of the main shaft  10  from the right end thereof as viewed in  FIG. 1 . The first speed drive gear  22 , the reverse drive gear  24 , and the second speed drive gear  26  are fixedly mounted on the main shaft  10  so as to be nonrotatable relative thereto. The third speed drive gear  28 , the fourth speed drive gear  30 , the fifth speed drive gear  32 , and the sixth speed drive gear  34  are idly mounted on the main shaft  10  so as to be rotatable relative thereto. 
     As well known in the art, the third speed drive gear  28  or the fourth speed drive gear  30  is fixed (connected) to the main shaft  10  by sliding a synchronizer sleeve  36   a  of the 3-4 speed synchromesh mechanism  36  in the rightward or leftward direction as viewed in  FIG. 1 . Similarly, the fifth speed drive gear  32  or the sixth speed drive gear  34  is fixed (connected) to the main shaft  10  by sliding a synchronizer sleeve  38   a  of the 5-6 speed synchromesh mechanism  38  in the rightward or leftward direction as viewed in  FIG. 1 . 
     There are provided on the counter shaft  16  a final drive gear  40 , a first speed driven gear  42 , a 1-2 speed synchromesh mechanism  54 , a second speed driven gear  44 , a third speed driven gear  46 , a fourth speed driven gear  48 , a fifth speed driven gear  50 , and a sixth speed driven gear  52 . These elements  40 ,  42 ,  54 ,  44 ,  46 ,  48 ,  50 , and  52  are arranged in this order in the axial direction of the counter shaft  16  from the right end thereof as viewed in  FIG. 1 . The final drive gear  40 , the third speed driven gear  46 , the fourth speed driven gear  48 , the fifth speed driven gear  50 , and the sixth speed driven gear  52  are fixedly mounted on the counter shaft  16  so as to be nonrotatable relative thereto. The first speed driven gear  42  and the second speed driven gear  44  are idly mounted on the counter shaft  16  so as to be rotatable relative thereto. 
     The first speed driven gear  42  or the second speed driven gear  44  is fixed (connected) to the counter shaft  16  by sliding a synchronizer sleeve  54   a  of the 1-2 speed synchromesh mechanism  54  in the rightward or leftward direction as viewed in  FIG. 1 . The synchronizer sleeve  54   a  of the 1-2 speed synchromesh mechanism  54  is integrally formed with a reverse driven gear  56 . A reverse idle gear  60  is idly mounted on a reverse shaft  58  so as to be rotatable relative thereto. By sliding the reverse idle gear  60  in the rightward direction as viewed in  FIG. 1  to bring it into mesh with the reverse drive gear  24  and the reverse driven gear  56 , the counter shaft  16  is rotated in the reverse direction opposite to the forward direction in forward running, thereby allowing reverse running. 
     Reference numeral  62  denotes a differential unit having a ring gear  64 . The ring gear  64  of the differential unit  62  is in mesh with the final drive gear  40 . An output from the differential unit  62  is transmitted to drive wheels (not shown) through drive shafts  70  and  72  respectively rotatably supported by bearings  66  and  68 . On the other hand, a drive force generated by an electric motor  74  is transmitted through a speed reducing mechanism  76  to the differential unit  62 . The speed reducing mechanism  76  has a primary shaft  78  connected to the output shaft of the electric motor  74  and a secondary shaft (drive shaft)  88  extending parallel to the primary shaft  78 . 
     The primary shaft  78  is rotatably supported by a pair of bearings  80  and  82 , and the secondary shaft  88  is rotatably supported by a pair of bearings  90  and  92 . A drive gear  84  is idly mounted on the primary shaft  78  so as to be rotatable relative thereto. The drive gear  84  is fixed (connected) to the primary shaft  78  by sliding a synchronizer sleeve  86   a  of a synchromesh mechanism (clutch mechanism)  86  in the rightward direction as viewed in  FIG. 1 . There are provided on the secondary shaft  88 , a driven gear  94 , a final drive gear  96 , and a parking gear  98 . These elements  94 ,  96 , and  98  are arranged in this order in the axial direction of the secondary shaft  88  from the right end thereof as viewed in  FIG. 1 . All of the driven gear  94 , the final drive gear  96 , and the parking gear  98  are fixedly mounted on the secondary shaft  88 . 
     In the case of running by the drive force of the engine  2 , the synchronizer sleeve  86   a  of the synchronizer mechanism (clutch mechanism)  86  provided on the primary shaft  78  is kept in its neutral position as shown in  FIG. 1 , and the clutch  6  is engaged. As a result, the drive force of the engine  2  is transmitted through the clutch  6  and the transmission  8  to the ring gear  64  of the differential unit  62 , thereby driving the drive wheels through the drive shafts  70  and  72 . 
     In the case of running by the drive force of the electric motor  74 , the clutch  6  is disengaged and the synchronizer sleeve  86   a  of the synchromesh mechanism  86  is slid in the rightward direction as viewed in  FIG. 1  to fix (connect) the drive gear  84  to the primary shaft  78 . As a result, the drive force of the electric motor  74  is transmitted through the primary shaft  78 , the drive gear  84 , the driven gear  94 , the secondary shaft  88 , and the final drive gear  96  to the ring gear  64  of the differential unit  62 , thereby driving the drive wheels (not shown) through the drive shafts  70  and  72 . 
     Reverse running is allowed by any one of the engine  2  and the electric motor  74 . In the case of reverse running by the engine  2 , the reverse idle gear  60  is slid in the rightward direction as viewed in  FIG. 1  to bring it into mesh with the reverse drive gear  24  and the reverse driven gear  56 . As a result, the counter shaft  16  is rotated in the reverse direction opposite to the forward direction in forward running, thereby allowing reverse running through the differential unit  62 . In the case of reverse running by the electric motor  74 , the drive gear  84  is fixed (connected) through the synchromesh mechanism  86  to the primary shaft  78 , and the rotational direction of the motor  74  is changed from the forward direction to the reverse direction. 
     Referring next to  FIGS. 2 to 5C , there is shown an actuator mechanism for selectively operating a clutch mechanism (synchromesh mechanism) and a parking mechanism in the drive force transmitting apparatus described above. 
       FIG. 2  is a perspective view of the actuator mechanism  99 ,  FIG. 3  is an elevational view of the actuator mechanism  99 , and  FIG. 4  is a perspective view of the actuator mechanism  99  as viewed from the back side thereof. As best shown in  FIG. 2 , a drive gear  102  is fixedly mounted on the output shaft of a motor  100 . Reference numeral  104  denotes a one-way camshaft. A sectorial driven gear  106  meshing with the drive gear  102  and a one-way cam  108  are fixedly mounted on the one-way camshaft  104 . Reference numeral  110  denotes a rotational angle sensor such as a resolver for detecting a rotational direction and rotational angle of the one-way camshaft  104 . 
     Reference numeral  112  denotes a fork shaft for operating the clutch mechanism  86 . A cam follower  116  having a U-shaped recess  116   a  and an operating fork  114  are fixedly mounted on the fork shaft  112 . The one-way cam  108  is inserted in the U-shaped recess  116   a  of the cam follower  116 . As shown in  FIG. 4 , the operating fork  114  is engaged with the synchronizer sleeve  86   a  of the synchromesh mechanism (clutch mechanism)  86 . In  FIG. 4 , reference numeral  87  denotes a stopper for preventing axial escape of the synchronizer sleeve  86   a . The stopper  87  is provided on a synchronizer hub (not shown) included in the synchromesh mechanism  86 . 
     The driven gear  106  is integrally formed with a mounting bracket  107 , and a ball-shaped pivot  118  is fixed to the mounting bracket  107  so as to project downward. The ball-shaped pivot  118  is inserted in a U-shaped recess  124   a  of a socket  124  fixed to a parking lever shaft  120 . The parking lever shaft  120  is rotatably supported, and a parking lever  122  is fixedly mounted on the parking lever shaft  120  so as to be biased counterclockwise as viewed in  FIG. 3  by a coil spring  126 . The counterclockwise rotation of the parking lever  122  is restricted by a stopper (not shown) provided in the parking lever  122 . 
     A parking pawl  130  is rotatably mounted on a parking pawl shaft  128  fixed. An engaging portion  130   a  is formed at one end of the parking pawl  130 . The engaging portion  130   a  of the parking pawl  130  is adapted to selectively engage the parking gear  98  shown in  FIG. 4 , thereby nonrotatably locking the secondary shaft  88  to which the parking gear  98  is fixed. The parking pawl  130  is biased clockwise as viewed in  FIG. 3  by a return spring  132 , and the other end  130   b  of the parking pawl  130  abuts against a stopper pin  134 , thereby restricting the clockwise rotation of the parking pawl  130 . 
     The operation of the actuator mechanism  99  will now be described. When the motor  100  is energized to counterclockwise rotate the one-way camshaft  104  through the drive gear  102  and the driven gear  106 , the one-way cam  108  is rotated counterclockwise as shown by an arrow  138  in  FIG. 5A  to thereby move the cam follower  116  in the direction shown by an arrow  140 . Accordingly, as shown in  FIGS. 2 and 4 , the fork shaft  112  and the operating fork  114  fixed to the fork shaft  112  are moved in the direction of the arrow  140 . As a result, the synchronizer sleeve  86   a  of the synchromesh mechanism  86  is moved in the rightward direction as viewed in  FIG. 1  to come into engagement with the drive gear  84 , so that the drive gear  84  is fixed (connected) through the synchromesh mechanism (clutch mechanism)  86  to the primary shaft  78 . 
     Accordingly, the drive force of the electric motor  74  is transmitted through the primary shaft  78 , the drive gear  84 , the driven gear  94 , the secondary shaft  88 , the final drive gear  96  to the differential unit  62 , thereby driving the drive wheels (not shown) through the drive shafts  70  and  72 . When the clutch  6  is engaged in this case, the drive force of the engine  2  is added to the drive force of the electric motor  74 , thereby obtaining a large drive torque. When the clutch  6  is disengaged, the vehicle is driven by the drive force of the electric motor  74  only, that is, the previous motor driven condition of the vehicle is restored. 
     In the case of canceling the running by the electric motor  74 , the rotational direction of the motor  100  is reversed to clockwise rotate the one-way camshaft  104 , thereby clockwise rotating the one-way cam  108  to the neutral condition shown in  FIG. 5B . As a result, the cam follower  116  is moved in the direction opposite to the direction of the arrow  140 , thereby disengaging the synchronozer sleeve  86   a  from the drive gear  84 . Accordingly, the drive gear  84  becomes rotatable relative to the primary shaft  78 , so that the drive force of the electric motor  74  is not transmitted to the secondary shaft  88 . 
     In the neutral condition of the one-way cam  108  as shown in  FIG. 5B , there is no possibility that the cam follower  116  may be moved by the one-way cam  108  because of vibrations, impact, etc. Conversely, in the event that the one-way cam  108  is rotated by a large external force due to vibrations, impact, etc. from the cam follower  116 , i.e., from the operating fork  114 , such a malfunction is immediately detected by the rotational angle sensor  110 , and the motor  100  is operated under feedback control in the direction reverse to the direction of the malfuction, thereby preventing the malfunction. 
     When the motor  100  is operated in the reverse direction from the neutral condition shown in  FIG. 5B  to clockwise rotate the one-way camshaft  104  through the drive gear  102  and the driven gear  106 , the parking lever shaft  120  is rotated counterclockwise as viewed in  FIG. 3  through the ball-shaped pivot  118  and the socket  124 . As a result, the parking lever  122  is rotated counterclockwise to push the other end  130   b  of the parking pawl  130 , so that the parking pawl  130  is rotated counterclockwise as shown by an arrow  144  in  FIG. 2  to thereby bring the engaging portion  130   a  into engagement with the parking gear  98 . Accordingly, the secondary shaft  88  is fixed in rotation by the parking pawl  130 , thus attaining a parking lock function. 
     At this time, the one-way cam  108  is rotated clockwise as shown by an arrow  142  in  FIG. 5C . In this clockwise rotation, the one-way cam  108  does not engage with the cam follower  116  at any position owing to the specific shapes of the one-way cam  108  and the cam follower  116  as shown in  FIG. 5C . In other words, the one-way cam  108  is rotated clockwise without interference with the cam follower  116 , i.e. the one-way cam  108  misses rotating in the cam follower  116  so that the movement of the operating fork  114  can be reliably prevented in performing the parking lock operation. 
     In the case of canceling the parking lock condition, the motor  100  is operated in the forward direction opposite to the operational direction in the parking lock operation, thereby counterclockwise rotating the one-way camshaft  104  to return the one-way cam  108  to the neutral condition shown in  FIG. 5B . As a result, the parking lever shaft  120  and the parking lever  122  are rotated clockwise as viewed in  FIG. 3 , so that the parking pawl  130  is rotated clockwise by the biasing force of the return spring  132 . As a result, the engaging portion  130   a  of the parking pawl  130  is disengaged from the parking gear  98 , thus canceling the parking lock condition. 
     According to the preferred embodiment mentioned above, the drive force transmitting apparatus includes the actuator mechanism  99  capable of selectively operating the clutch mechanism  86  and the parking mechanism. Accordingly, as compared with the case that any dedicated selector apparatus is provided for each mechanism, the number of parts can be greatly reduced to thereby greatly reduce the cost and weight of the drive force transmitting apparatus. 
     Further, in the case that the parking mechanism is operated to effect the lock condition of the vehicle, the clutch mechanism  86  is always kept in its disengaged condition. Conversely, in the case that the clutch mechanism  86  is operated to effect the on-line condition where the electric motor  74  is connected with the drive force transmitting path, the parking mechanism is not operated. Accordingly, it is possible to attain a fail-safe function. That is, a malfunction such that the parking mechanism is operated during running by the electric motor  74  can be reliably prevented. 
     The present invention is not limited to the details of the above described preferred embodiments. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalence of the scope of the claims are therefore to be embraced by the invention.