Patent Publication Number: US-2019195362-A1

Title: Interlock mechanism

Description:
TECHNICAL FIELD 
     The present invention relates to an interlock mechanism of a transmission. 
     BACKGROUND ART 
     In the related art, for example, as disclosed in PTL 1 below, an interlock structure is known which prevents movement of an unselected fork when a shift operation is performed by a driver. An interlock mechanism in the related art has a shift and select shaft pivoting in conjunction with a select operation, and an interlock rod disposed in parallel with the shift and select shaft and pivoting in conjunction with the pivoting of the shift and select shaft, an interlock arm fixed to the interlock rod and engaged with each fork or disengaged from each fork in accordance with an angular position of the interlock rod in a pivoting direction. In the interlock mechanism in the related art, a select arm fixed to the shift and select shaft is connected to a select bracket fixed to the interlock rod so that the interlock rod pivots in conjunction with the shift and select shaft. 
     CITATION LIST 
     Patent Literature 
     PTL 1: JP-A-2009-168217 
     SUMMARY OF INVENTION 
     Technical Problem 
     Incidentally, the interlock mechanism in the related art has the interlock rod, the select arm, and the select bracket. Therefore, the interlock mechanism in the related art has a complicated and large structure, and assembly work is cumbersome, thereby increasing the cost of the interlock mechanism. 
     The present invention is made in order to solve the above-described problem, that is, an object of the present invention is to provide an interlock mechanism capable of achieving a simple and miniaturized structure. 
     Solution to Problem 
     According to the invention related to claim  1 , in order to solve the above-described problem, there is provided an interlock mechanism including a shift select shaft disposed to be movable along an axial direction and rotatable in a rotation direction, a first fork disposed to face the shift select shaft, a second fork disposed to face the shift select shaft, a first inner lever disposed in the shift select shaft, engaging with the first fork in a state where the shift select shaft is located at a first rotation position, and disengaging from the first fork in a state where the shift select shaft is located at a second rotation position different from the first rotation position, a second inner lever disposed in the shift select shaft, engaging with the second fork in a state where the shift select shaft is located at a third rotation position different from the first rotation position, and disengaging from the second fork in a state where the shift select shaft is located at a fourth rotation position different from the third rotation position, and an interlock member rotated integrally with the shift select shaft in the rotation direction, and disposed to be immovable in the axial direction. The first fork has a first engagement portion engaging with the first inner lever located at the first rotation position, and the second fork has a second engagement portion engaging with the second inner lever located at the third rotation position. The interlock member includes a first main body portion disposed coaxially with the shift select shaft on an outer peripheral side of the shift select shaft, a second main body portion different from the first main body portion, and a connection pin connecting the first main body portion and the second main body portion to each other so that the first main body portion and the second main body portion are integrally rotated in the rotation direction. The first main body portion has a first engagement target portion engaging with the first engagement portion in a state where the first main body portion is located at the third rotation position. The second main body portion has a second engagement target portion engaging with the second engagement portion in a state where the second main body portion is located at the first rotation position. 
     According to this configuration, the interlock member can be configured to include the first main body portion formed with the first engagement target portion, the second main body portion formed with the second engagement target portion, and the connection pin integrally rotating the first main body portion and the second main body portion in the rotation direction of the shift select shaft. Then, the interlock member configured in this way is coaxially disposed on the outer peripheral side of the shift select shaft. According to this simple configuration, it is possible to achieve the interlock mechanism in which the first engagement portion of the first fork and the second engagement portion of the second fork engage with or disengage from each other in accordance with the position in the rotation direction of the shift select shaft. In this manner, a structure of the interlock mechanism can be simplified, and the miniaturized interlock mechanism can be achieved. In addition to the simplified structure of the interlock mechanism, the interlock member is divided into the first main body portion and the second main body portion. Accordingly, the interlock mechanism can be easily assembled to the shift select shaft. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a view for describing a transmission. 
         FIG. 2  is a perspective view of a shift mechanism. 
         FIG. 3  is a perspective view for explaining a configuration of an interlock mechanism in  FIG. 2 . 
         FIG. 4  is a view for explaining a shift pattern. 
         FIG. 5  is a perspective view for explaining a second inner lever, a third inner lever, and an interlock member. 
         FIG. 6  is a perspective view for explaining a first main body portion in  FIG. 5 . 
         FIG. 7  is a perspective view for explaining a second main body portion in  FIG. 5 . 
         FIG. 8A  is a view illustrating a positional relationship between a first fork and the interlock member when first-second gear shift is selected. 
         FIG. 8B  is a view illustrating a positional relationship between the first fork and the interlock member when third-fourth gear shift is selected. 
         FIG. 8C  is a view illustrating a positional relationship between the first fork and the interlock member when fifth-sixth gear shift is selected. 
         FIG. 8D  is a view illustrating a positional relationship between the first fork and the interlock member when reverse shift is selected. 
         FIG. 9A  is a view illustrating a positional relationship between a second fork and the interlock member when the first-second gear shift is selected. 
         FIG. 9B  is a view illustrating a positional relationship between the second fork and the interlock member when the third-fourth gear shift is selected. 
         FIG. 9C  is a view illustrating a positional relationship between the second fork and the interlock member when the fifth-sixth gear shift is selected. 
         FIG. 9D  is a view illustrating a positional relationship between the second fork and the interlock member when the reverse shift is selected. 
         FIG. 10A  is a view illustrating a positional relationship between a third fork and the interlock member when the first-second gear shift is selected. 
         FIG. 10B  is a view illustrating a positional relationship between the third fork and the interlock member when the third-fourth gear shift is selected. 
         FIG. 10C  is a view illustrating a positional relationship between the third fork and the interlock member when the fifth-sixth gear shift is selected. 
         FIG. 10D  is a view illustrating a positional relationship between the third fork and the interlock member when the reverse shift is selected. 
         FIG. 11A  is a view illustrating a positional relationship between a reverse fork and the interlock member when the first-second gear shift is selected. 
         FIG. 11B  is a view illustrating a positional relationship between the reverse fork and the interlock member when the third-fourth gear shift is selected. 
         FIG. 11C  is a view illustrating a positional relationship between the reverse fork and the interlock member when the fifth-sixth gear shift is selected. 
         FIG. 11D  is a view illustrating a positional relationship between the reverse fork and the interlock member when the reverse shift is selected. 
         FIG. 12  is a perspective view for explaining an interlock member according to a modification example of an embodiment of the interlock mechanism in the present invention. 
         FIG. 13  is a partial sectional view for explaining an assembled state of the interlock member illustrated in  FIG. 12 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     (Structure of Transmission) 
     A transmission  100  according to the present embodiment will be described with reference to  FIG. 1 . In  FIG. 1 , an arrangement side of an engine  11  will be referred to as forward of the transmission  100 , and an arrangement side of a differential (DF)  17  will be referred to as a rearward of the transmission  100 . In addition, a forward-rearward direction of the transmission  100  will be referred to as an axial direction. 
     As illustrated in  FIG. 1 , the transmission  100  according to the present embodiment has an input shaft  101 , an output shaft  102 , a counter shaft  103 , a first drive gear  111  to a sixth drive gear  116 , a first driven gear  121  to a sixth driven gear  126 , an output shaft side reduction gear  131 , a counter shaft side reduction gear  132 , a reverse drive gear  141 , a reverse driven gear  142 , an idler shaft  143 , a reverse idler gear  144 , a first hub H 1  to a third hub H 3 , a first fork F 1  to a third fork F 3 , and a reverse fork FR. 
     The input shaft  101 , the output shaft  102 , and the counter shaft  103  are rotatably disposed in a housing (not illustrated) of the transmission  100 . The input shaft  101  is connected to a clutch  12 , and a rotational torque from the engine  11  is input to the input shaft  101  via the clutch  12 . The output shaft  102  is disposed behind the input shaft  101  so as to be coaxial with the input shaft  101 . The differential (DF)  17  for absorbing a rotational speed difference between drive wheels  18 R and  18 L is connected to the output shaft  102 . The counter shaft  103  is disposed in parallel with the input shaft  101  and the output shaft  102 . 
     The first drive gear  111  and the second drive gear  112  are fixed to the input shaft  101 . The fifth drive gear  115 , the sixth drive gear  116 , and the third drive gear  113  are disposed in the input shaft  101  so as to be idly rotatable. In the present embodiment, the first drive gear  111 , the second drive gear  112 , the fifth drive gear  115 , the sixth drive gear  116 , the third drive gear  113  are disposed in this order from the front to the rear of the input shaft  101 . 
     The first driven gear  121  and the second driven gear  122  are disposed in the counter shaft  103  so as to be idly rotatable. The fifth driven gear  125 , the sixth driven gear  126 , and the third driven gear  123  are fixed to the counter shaft  103 . In the present embodiment, the first driven gear  121 , the second driven gear  122 , the fifth driven gear  125 , the sixth driven gear  126 , and the third driven gear  123  are disposed in this order from the front to the rear of the counter shaft  103 . 
     The first drive gear  111  and the first driven gear  121  mesh with each other. The second drive gear  112  and the second driven gear  122  mesh with each other. The third drive gear  113  and the third driven gear  123  mesh with each other. The fifth drive gear  115  and the fifth driven gear  125  mesh with each other. The sixth drive gear  116  and the sixth driven gear  126  mesh with each other. 
     A gear diameter increases in the order of the first drive gear  111 , the second drive gear  112 , the third drive gear  113 , the fifth drive gear  115 , and the sixth drive gear  116 . A gear diameter decreases in the order of the first driven gear  121 , the second driven gear  122 , the third driven gear  123 , the fifth driven gear  125 , and the sixth driven gear  126 . The gear diameter of the fifth drive gear  115  is larger than that of the fifth driven gear  125 . 
     The output shaft side reduction gear  131  is disposed on the output shaft  102 . The counter shaft side reduction gear  132  is disposed on the counter shaft  103 . The output shaft side reduction gear  131  and the counter shaft side reduction gear  132  mesh with each other. The gear diameter of the counter shaft side reduction gear  132  is smaller than the gear diameter of the output shaft side reduction gear  131 . Therefore, rotational speed of the engine  11  (more specifically, the input shaft  101 ) is reduced between the counter shaft side reduction gear  132  and the output shaft side reduction gear  131 , and the rotational torque from the engine  11  increases. 
     The idler shaft  143  is rotatably disposed in the housing of the transmission  100  in parallel with the input shaft  101  and the counter shaft  103 . The reverse drive gear  141  is fixed to the input shaft  101 . The reverse driven gear  142  is fixed to the counter shaft  103 . The reverse idler gear  144  is disposed in the idler shaft  143  so as to be movable in the axial direction (forward-rearward direction). The reverse idler gear  144  engages with the reverse fork FR. The reverse idler gear  144  meshes with the reverse drive gear  141  and the reverse driven gear  142 , and does not mesh with the reverse drive gear  141  and the reverse driven gear  142 . 
     The first hub H 1  is disposed between the first driven gear  121  and the second driven gear  122  so as not to be rotatable relative to the counter shaft  103  and so as to be movable in the axial direction. The first hub H 1  engages with a connection portion F 1   c  (refer to  FIG. 2 ) of the first fork F 1 . In accordance with a position in the axial direction, the first hub H 1  engages with or disengages from any one of a first engagement-disengagement portion E 1  formed in the first driven gear  121  and a second engagement-disengagement portion E 2  formed in the second driven gear  122 . 
     The second hub H 2  is disposed between the third drive gear  113  and the output shaft  102  so as not to be rotatable relative to the input shaft  101  and so as to be movable in the axial direction. The second hub H 2  engages with a connection portion F 2   c  (refer to  FIG. 2 ) of the second fork F 2 . In accordance with a position in the axial direction, the second hub H 2  engages with or disengages from any one of a third engagement-disengagement portion E 3  formed in the third drive gear  113  and a fourth engagement-disengagement portion E 4  formed in the output shaft  102 . 
     The third hub H 3  is disposed between the fifth drive gear  115  and the sixth drive gear  116  so as not to be rotatable relative to the input shaft  101  and so as to be movable in the axial direction. The third hub H 3  engages with a connection portion F 3   c  (refer to  FIG. 2 ) of the third fork F 3 . In accordance with a position in the axial direction, the third hub H 3  engages with or disengages from any one of a fifth engagement-disengagement portion E 5  formed in the fifth drive gear  115  and a sixth engagement-disengagement portion E 6  formed in the sixth drive gear  116 . 
     A synchronizer mechanism for synchronizing the rotational speed difference between the respective hub H 1  to hub H 3  and the respective engagement-disengagement portion E 1  to engagement-disengagement portion E 6  is disposed between the respective hub H 1  to hub H 3  and the respective engagement-disengagement portion E 1  to engagement-disengagement portion E 6 . The synchronizer mechanism is a well-known technology, and thus, description thereof will be omitted. 
     (Shift Mechanism) 
     Hereinafter, a shift mechanism  10  will be described with reference to  FIGS. 2 to 11 . The shift mechanism  10  forms a gear shifting stage of the transmission  100 . As illustrated in  FIG. 2 , the shift mechanism  10  includes a shift select shaft  1 , a shift outer lever  2 , a select outer lever  3 , an interlock member  4 , a reverse fork shaft  5 , and a reverse fork connection member  6 . Furthermore, the shift mechanism  10  includes the first fork F 1  to the third fork F 3 , the reverse fork FR, a first inner lever e 1  to a third inner lever e 3 , and a reverse inner lever er. 
     The shift select shaft  1  (hereinafter, simply referred to as a “shaft  1 ”) is disposed in the housing of the transmission  100  so as to be movable along the axial direction and rotatable around an axis. As illustrated in  FIG. 3 , a tip portion on a front side of the shaft  1  has a groove portion  1   b  engaging with a lock ball member (not illustrated). As illustrated in  FIGS. 2 and 3 , a shift select shaft head  1   a  is fixed to the front side of the shaft  1 . As illustrated in  FIG. 2 , the shift outer lever  2  and the select outer lever  3  are connected to the shift select shaft head  1   a  via a well-known link mechanism. The shift outer lever  2  and the select outer lever  3  are respectively connected to a shift lever  990  (refer to  FIG. 4 ) disposed in a driver&#39;s seat via a gear shift cable (not illustrated). 
     If the shift lever  990  is moved in a shift direction (refer to  FIG. 4 ), an operation force input to the shift lever  990  is transmitted to the shift outer lever  2  via the gear shift cable, and the shift outer lever  2  pivots. In this way, the shift outer lever  2  pivots and the operation force input to the shift lever  990  is transmitted to the shaft  1 , thereby moving the shaft  1  in the axial direction. 
     If the shift lever  990  is moved in the select direction (refer to  FIG. 4 ), the operation force input to the shift lever  990  is transmitted to the select outer lever  3  via the gear shift cable, and the select outer lever  3  pivots. In this way, the select outer lever  3  pivots and the operation force input to the shift lever  990  is transmitted to the shaft  1 , thereby rotating the shaft  1  around the axis. 
     Here, referring to  FIG. 4 , a shift pattern  950  which indicates a movable range of the shift lever  990  will be described. In the shift pattern  950 , a reverse shift gate  950   a,  a first-second gear shift gate  950   b,  a third-fourth gear shift gate  950   c,  and a fifth-sixth gear shift gate  950   d  are arranged in parallel with each other, and neutral positions thereof communicate with each other via a select gate  950   e.  The reverse shift gate  950   a,  the first-second gear shift gate  950   b,  the third-fourth gear shift gate  950   c,  and the fifth-sixth gear shift gate  950   d  are formed in the shift direction which is the forward-rearward direction. In addition, the neutral position of the first-second gear shift gate  950   b,  the third-fourth gear shift gate  950   c,  and the fifth-sixth gear shift gate  950   d  is an intermediate position of the shift direction. In addition, the neutral position of the reverse shift gate  950   a  is located at a terminal of the reverse shift gate  950   a , and is a lower end of the reverse shift gate  950   a  in the present embodiment. In addition, the select gate  950   e  is formed in the select direction which is a rightward-leftward direction. 
     Referring back to  FIG. 2 , the forks are disposed facing each other across the shaft  1  in the order of the first fork F 1 , the third fork F 3 , and the second fork F 2  from the front to the rear. The first fork F 1  to the third fork F 3  are gate-type swing forks, and respectively include a main body portion F 1   a  to a main body portion F 3   a,  a support portion F 1   b  to a support portion F 3   b,  a connection portion F 1   c  to a connection portion F 3   c.  The main body portion F 1   a , the main body portion F 2   a,  and the main body portion F 3   a  have substantially a C-shape. As illustrated in  FIG. 2 , a fork head F 1   d  serving as a first engagement portion integrally protrudes on an upper surface side of the main body portion F 1   a  of the first fork F 1 . In addition, as illustrated in  FIG. 2 , a fork head F 2   d  and a fork head F 3   d  respectively serving as a second engagement portion protrude on a lower surface side of the main body portion F 2   a  of the second fork F 2  and the main body portion F 3   a  of the third fork F 3 , that is, on a surface facing the shaft  1 . 
     The support portion F 1   b , the support portion F 2   b,  and the support portion F 3   b  are disposed on both side portions of each of the main body portion F 1   a  to the main body portion F 3   a.  A pair of the support portions F 1   b  to the support portions F 3   b  is fixed to the housing of the transmission  100 . In this manner, the first fork F 1  to the third fork F 3  are attached to the housing so as to be swingable. 
     As illustrated in  FIG. 2 , the reverse fork shaft  5  is attached to the housing of the transmission  100  while a longitudinal direction of the reverse fork shaft  5  is set as the axial direction. The reverse fork FR is attached to the reverse fork shaft  5  so as to be movable in the axial direction. The reverse fork connection member  6  connects the reverse fork FR and the reverse fork shaft  5  to each other. A reverse engagement portion  6   a  is disposed in the reverse fork connection member  6 . 
     As illustrated in  FIG. 2 , the first inner lever e 1  is formed integrally with the shift select shaft head  1   a , and is fixed to the shaft  1  together with the shift select shaft head  1   a . As illustrated in  FIGS. 2 and 5 , the second inner lever e 2 , the third inner lever e 3 , and the reverse inner lever er are fixed to the shaft  1  by using pins, for example. As illustrated in  FIG. 2 , the first inner lever e 1  engages with the fork head F 1   d  of the first fork F 1  or disengages from the fork head F 1   d . The second inner lever e 2  engages with the fork head F 2   d  of the second fork F 2  or disengages from the fork head F 2   d.  The third inner lever e 3  engages with the fork head F 3   d  of the third fork F 3  or disengages from the fork head F 3   d.  The reverse inner lever er engages with the reverse engagement portion  6   a  of the reverse fork connection member  6  or disengages from the reverse engagement portion  6   a.    
     Depending on an angle of the shaft  1  in the rotation direction, any one of the first inner lever e 1  to the third inner lever e 3  and the reverse inner lever er selectively engages with any one of the fork head F 1   d , the fork head F 2   d,  the fork head F 3   d,  and the reverse engagement portion  6   a  which are located at positions corresponding to the inner levers. 
     Specifically, in a case where the shift lever  990  is located in the first-second gear shift gate  950   b,  the shaft  1  is located at a first rotation position R 1 . As illustrated in  FIG. 8A , the first inner lever e 1  engages with the fork head F 1   d  (first fork F 1 ). On the other hand, as illustrated in  FIGS. 8B to 8D , in a case where the shaft  1  is located at a second rotation position R 2  different from the first rotation position R 1 , the first inner lever e 1  disengages from the fork head F 1   d  (first fork F 1 ). 
     In a case where the shift lever  990  is located in the third-fourth gear shift gate  950   c,  the shaft  1  is located at a third rotation position R 3  different from the first rotation position R 1 , which is a position further rotated toward a forward rotation side from the first rotation position R 1 . As illustrated in  FIG. 9B , the second inner lever e 2  engages with the fork head F 2   d  (second fork F 2 ). On the other hand, as illustrated in  FIGS. 9A, 9C, and 9D , in a case where the shaft  1  is located at a fourth rotation position R 4  different from the third rotation position R 3 , the second inner lever e 2  disengages from the fork head F 2   d  (second fork F 2 ). 
     In a case where the shift lever  990  is located in the fifth-sixth gear shift gate  950   d,  the shaft  1  is located at a fifth rotation position R 5  different from the first rotation position R 1  and the third rotation position R 3 , which is a position further rotated toward the forward rotation side from the third rotation position R 3 . As illustrated in  FIG. 10C , the third inner lever e 3  engages with the fork head F 3   d  (third fork F 3 ). On the other hand, as illustrated in  FIGS. 10A, 10B , and  10 D, in a case where the shaft  1  is located at a sixth rotation position R 6  different from the fifth rotation position R 5 , the third inner lever e 3  disengages from the fork head F 3   d  (third fork F 3 ). 
     In a case where the shift lever  990  is located in the reverse shift gate  950   a  and the shaft  1  is located at a reverse rotation position RF which is a position rotated to a reverse rotation side from the first rotation position R 1 , as illustrated in  FIG. 11D , the reverse inner lever er engages with the reverse engagement portion  6   a  (reverse fork FR). On the other hand, as illustrated in  FIGS. 11A, 11B, and 11C , in a case where the shaft  1  is located at a seventh rotation position R 7  different from the reverse rotation position RF, the reverse inner lever er disengages from the reverse engagement portion  6   a  (reverse fork FR). 
     The second rotation position R 2  includes the third rotation position R 3  to the seventh rotation position R 7  and the reverse rotation position RF. The fourth rotation position R 4  includes the first rotation position R 1  to the third rotation position R 3 , the fifth rotation position R 5  to the seventh rotation position R 7 , and the reverse rotation position RF. The sixth rotation position R 6  includes the first rotation position R 1  to the fifth rotation position R 5 , the seventh rotation position R 7 , and the reverse rotation position RF. The seventh rotation position R 7  includes the first rotation position R 1  to the sixth rotation position R 6  and the reverse rotation position RF. 
     In a state where any one of the first inner lever e 1  to the third inner lever e 3  engages with any one of the fork head F 1   d  to the fork head F 3   d  located at positions corresponding to the inner levers, if the shift lever  990  is moved to an odd number stage side in the shift direction, the shaft  1  moves rearward. If the shaft  1  moves rearward, the first fork F 1  to the third fork F 3  engaging with any one of the first inner lever e 1  to the third inner lever e 3  swings. The connection portion F 1   c  to the connection portion F 3   c  of the swung first fork F 1  to third fork F 3  move forward. Then, the hub H 1  to the hub H 3  engaging with the moved connection portion F 1   c  to connection portion F 3   c  move forward. In this manner, a gear shifting stage corresponding to the moved hub H 1  and hub H 3  is formed. That is, any one of the first gear, the third gear, and the fifth gear is formed in the transmission  100 . 
     In a state where any one of the first inner lever e 1  to the third inner lever e 3  engages with any one of the fork head F 1   d  to the fork head F 3   d  located at positions corresponding to the inner levers, if the shift lever  990  is moved to an even number stage side in the shift direction, the shaft  1  moves forward. If the shaft  1  moves forward, the first fork F 1  to the third fork F 3  engaging with any one of the first inner lever e 1  to the third inner lever e 3  swings. The connection portion F 1   c  to the connection portion F 3   c  of the swung first fork F 1  to third fork F 3  move rearward. Then, the hub H 1  to the hub H 3  engaging with the moved connection portion F 1   c  to connection portion F 3   c  move rearward. In this manner, a gear shifting stage corresponding to the moved hub H 1  and hub H 3  is formed. That is, any one of the second gear, the fourth gear, and the sixth gear is formed in the transmission  100 . 
     In addition, in a state where the reverse inner lever er engages with the reverse engagement portion  6   a,  if the shift lever  990  is moved to the odd number stage side in the shift direction, the shaft  1  moves rearward. If the shaft  1  moves rearward, the reverse fork FR moves rearward together with the reverse fork shaft  5  connected to the reverse fork connection member  6 , and the reverse gear is formed in the transmission  100 . 
     (Interlock Mechanism) 
     Hereinafter, an interlock mechanism  10   a  will be described with reference to  FIGS. 2 to 7 . In a case where the shaft  1  and any one fork of the first fork F 1  to the third fork F 3  are connected and selected, the interlock mechanism  10   a  prevents, the swinging of the first fork F 1  to the third fork F 3  except for the selected fork. The interlock mechanism  10   a  is configured to include the interlock member  4 , the first fork F 1  to the third fork F 3 , and the reverse fork connection member  6 . 
     As illustrated in  FIG. 3 , the interlock member  4  has a first main body portion  41  and a second main body portion  42  which are arranged rearward from the front, and a connection pin  43  connecting the first main body portion  41  and the second main body portion  42  to each other. The first main body portion  41  has substantially a cylindrical shape, and is located to surround the shift select shaft head la of the shaft  1 . As illustrated in detail in  FIGS. 5 and 6 , the first main body portion  41  has a pair of two communication hole  41   a  and communication hole  41   b  communicating with each other in the forward-rearward direction. The shaft  1  is inserted into the communication holes  41   a  and  41   b  of the first main body portion  41 . In this manner, the first main body portion  41  is disposed coaxially with the shaft  1  on the outer peripheral side of the shaft  1 . 
     The first main body portion  41  is disposed in the shaft  1  while accommodating the shift select shaft head  1   a  (more specifically, the first inner lever e 1 ). In this manner, the first main body portion  41  is rotated integrally with the shaft  1 . On the other hand, the shaft  1  is movable relative to the first main body portion  41  in the forward-rearward direction. The first main body portion  41  is restricted in moving in the forward-rearward direction (axial direction) by the housing of the transmission  100 , and is immovable in the axial direction. 
     As illustrated in  FIGS. 5 and 6 , a first engagement target portion  41   c  extending in a direction orthogonal to the axial direction of the shaft  1  is formed by cutting out the first main body portion  41 . The first main body portion  41  has a slit  41   d  in the forward-rearward direction (axial direction of the shaft  1 ) so as to traverse the first engagement target portion  41   c.  Depending on a position in the rotation direction of the first main body portion  41  (that is, the interlock member  4 ), the first engagement target portion  41   c  engages with the fork head F 1   d , or disengages from the fork head F 1   d . The slit  41   d  accommodates the first inner lever e 1 . Whereas the slit  41   d  allows the first inner lever e 1  to move in the axial direction relative to the first main body portion  41  (that is, the interlock member  4 ), the slit  41   d  restricts the first inner lever e 1  in moving in the rotation direction relative to the first main body portion  41  (that is, the interlock member  4 ). 
     As illustrated in detail in  FIGS. 5 and 7 , the second main body portion  42  has a semi-cylindrical shape. A first plate portion  421  is connected to the front side (one end side) adjacent to the first main body portion  41 , and a second plate portion  422  is connected to the rear side (the other end side) of the second main body portion  42 . The first plate portion  421  and the second plate portion  422  are integrally connected to the second main body portion  42  by means of welding, for example. 
     As illustrated in  FIG. 7 , the first plate portion  421  is formed in a substantially annular shape, and has a communication hole  421   a  communicating in the forward-rearward direction. In addition, the first plate portion  421  has a pin engagement portion  421   b  engaging with the connection pin  43 . As illustrated in  FIG. 7 , the second plate portion  422  is formed in a substantially annular shape, and has a communication hole  422   a  communicating in the forward-rearward direction. In addition, the second plate portion  422  has a welding portion  422   b  to be welded to the second main body portion  42 . The welding portion  422   b  is welded in a state of being folded back and brought into contact with the second main body portion  42 . The shaft  1  is inserted into the communication hole  421   a  of the first plate portion  421  forming the second main body portion  42  and the communication hole  422   a  of the second plate portion  422 . In this manner, the second main body portion  42  is disposed coaxially with the shaft  1  on the outer peripheral side of the shaft  1 . 
     In addition, the second main body portion  42  has a recess portion  42   a  for accommodating the connection pin  43 . As illustrated in  FIG. 3 , the proximal end side of the connection pin  43  is fixed to the shift select shaft head  1   a  so as not to be detachable therefrom. As illustrated in  FIG. 3 , the connection pin  43  engages with the pin engagement portion  421   b  of the first plate portion  421  and the recess portion  42   a  of the second main body portion  42 . In this manner, the second main body portion  42  is rotated integrally with the first main body portion  41 , that is, the shaft  1 . On the other hand, the shaft  1  is movable in the forward-rearward direction relative to the second main body portion  42 . The second main body portion  42  is restricted in moving in the forward-rearward direction (axial direction) by the housing of the transmission  100 , and is immovable in the axial direction. 
     As illustrated in detail in  FIGS. 5 and 7 , a second engagement target portion  42   b  extending in a direction orthogonal to the axial direction of the shaft  1  is formed by cutting out the rear side of the second main body portion  42 . The second main body portion  42  has a slit  42   c  in the forward-rearward direction (axial direction of the shaft  1 ) so as to traverse the second engagement target portion  42   b.  Depending on a position in the rotation direction of the second main body portion  42  (that is, the interlock member  4 ), the second engagement target portion  42   b  engages with the fork head F 2   d,  or disengages from the fork head F 2   d.  The slit  42   c  accommodates the second inner lever e 2 . Whereas the slit  42   c  allows the second inner lever e 2  to move in the axial direction relative to the second main body portion  42  (that is, the interlock member  4 ), the slit  42   c  restricts the second inner lever e 2  in moving in the rotation direction relative to the second main body portion  42  (that is, the interlock member  4 ). 
     As illustrated in detail in  FIGS. 5 and 7 , a third engagement target portion  42   d  extending in the direction orthogonal to the axial direction of the shaft  1  is formed by cutting out the front side of the second main body portion  42 . The second main body portion  42  has a slit  42   e  in the forward-rearward direction (axial direction of the shaft  1 ) so as to traverse the third engagement target portion  42   d.  Depending on a position in the rotation direction of the second main body portion  42  (that is, the interlock member  4 ), the third engagement target portion  42   d  engages with the fork head F 3   d,  or disengages from the fork head F 3   d.  The slit  42   e  accommodates the third inner lever e 3 . Whereas the slit  42   e  allows the third inner lever e 3  to move in the axial direction relative to the second main body portion  42  (that is, the interlock member  4 ), the slit  42   e  restricts the third inner lever e 3  in moving in the rotation direction relative to the second main body portion  42  (that is, the interlock member  4 ). 
     (Operation of Interlock Member) 
     Hereinafter, an operation of the interlock member  4  will be described with reference to  FIGS. 8 to 11 . In a state where the shift lever  990  is located in the first-second gear shift gate  950   b  and the shaft  1  is located at the first rotation position R 1 , as illustrated in  FIG. 8A , the fork head F 1   d  engages with the first inner lever e 1 . Then, the fork head F 1   d  and the first inner lever e 1  are located inside the first engagement target portion  41   c  at a position where the slit  41   d  of the first main body portion  41  is formed. Therefore, the first fork F 1  is movable (swingable) in the axial direction. If the shift lever  990  is moved to the odd number stage side or the even number stage side in the shift direction and the shaft  1  is moved in the axial direction, the first fork F 1  swings in the axial direction, and the first gear or the second gear is formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the first-second gear shift gate  950   b  and the shaft  1  is located at the first rotation position R 1 , as illustrated in  FIG. 9A , the fork head F 2   d  of the second fork F 2  does not engage with the second inner lever e 2 . Then, the fork head F 2   d  engages with the second engagement target portion  42   b  of the second main body portion  42 . Therefore, the second fork F 2  is prevented from moving (swinging) in the axial direction. Accordingly, the third gear or the fourth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the first-second gear shift gate  950   b  and the shaft  1  is located at the first rotation position R 1 , as illustrated in  FIG. 10A , the fork head F 3   d  of the third fork F 3  does not engage with the third inner lever e 3 . Then, the fork head F 3   d  engages with the third engagement target portion  42   d  of the second main body portion  42 . Therefore, the third fork F 3  is prevented from moving (swinging) in the axial direction. Accordingly, the fifth gear or the sixth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the first-second gear shift gate  950   b  and the shaft  1  is located at the first rotation position R 1 , as illustrated in  FIG. 11A , the reverse engagement portion  6   a  of the reverse fork connection member  6  does not engage with the reverse inner lever er. Therefore, the reverse fork FR is prevented from moving in the axial direction. Accordingly, the reverse gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the third-fourth gear shift gate  950   c  and the shaft  1  is located at the third rotation position R 3 , as illustrated in  FIG. 8B , the fork head F 1   d  of the first fork F 1  does not engage with the first inner lever e 1 . Then, the fork head F 1   d  is located inside the first engagement target portion  41   c  on the further rear side than the position where the slit  41   d  of the first main body portion  41  is formed. Therefore, the first fork F 1  is prevented from moving (swinging) in the axial direction. Accordingly, the first gear or the second gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the third-fourth gear shift gate  950   c  and the shaft  1  is located at the third rotation position R 3 , as illustrated in  FIG. 9B , the fork head F 2   d  of the second fork F 2  engages with the second inner lever e 2 . Then, the fork head F 2   d  and the second inner lever e 2  are located inside the second engagement target portion  42   b  at the position where the slit  42   c  of the second main body portion  42  is formed. Therefore, the second fork F 2  is movable (swingable) in the axial direction. The shift lever  990  is moved to the odd number stage side or the even number stage side in the shift direction. If the shaft  1  is moved in the axial direction, the second fork F 2  swings in the axial direction. Accordingly, the third gear or the fourth gear is formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the third-fourth gear shift gate  950   c  and the shaft  1  is located at the third rotation position R 3 , as illustrated in  FIG. 10B , the fork head F 3   d  of the third fork F 3  does not engage with the third inner lever e 3 . Then, the fork head F 3   d  is located inside the third engagement target portion  42   d  on the further rear side than the position where the slit  42   e  of the second main body portion  42  is formed. Therefore, the third fork F 3  is prevented from moving (swinging) in the axial direction. Accordingly, the fifth gear or the sixth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the third-fourth gear shift gate  950   c  and the shaft  1  is located at the third rotation position R 3 , as illustrated in  FIG. 11B , the reverse engagement portion  6   a  of the reverse fork connection member  6  does not engage with the reverse inner lever er. Therefore, the reverse fork FR is prevented from moving in the axial direction. Accordingly, the reverse gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the fifth-sixth gear shift gate  950   d  and the shaft  1  is located at the fifth rotation position R 5 , as illustrated in  FIG. 8C , the fork head F 1   d  of the first fork F 1  does not engage with the first inner lever e 1 . Then, the fork head F 1   d  is located inside the first engagement target portion  41   c  on the further rear side than the position where the slit  41   d  of the first main body portion  41  is formed. Therefore, the first fork F 1  is prevented from moving (swinging) in the axial direction. Accordingly, the first gear or the second gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the fifth-sixth gear shift gate  950   d  and the shaft  1  is located at the fifth rotation position R 5 , as illustrated in  FIG. 9C , the fork head F 2   d  of the second fork F 2  does not engage with the second inner lever e 2 . Then, the fork head F 2   d  is located inside the second engagement target portion  42   b  on the further rear side than the position where the slit  42   c  of the second main body portion  42  is formed. Therefore, the second fork F 2  is prevented from moving (swinging) in the axial direction. Accordingly, the third gear or the fourth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the fifth-sixth gear shift gate  950   d  and the shaft  1  is located at the fifth rotation position R 5 , as illustrated in  FIG. 10C , the fork head F 3   d  of the third fork F 3  engages with the third inner lever e 3 . Then, the fork head F 3   d  and the third inner lever e 3  are located inside the third engagement target portion  42   d  at the position where the slit  42   e  of the second main body portion  42  is formed. Therefore, the third fork F 3  is movable (swingable) in the axial direction. The shift lever  990  is moved to the odd number stage side or the even number stage side in the shift direction. If the shaft  1  is moved in the axial direction, the third fork F 3  swings in the axial direction. Accordingly, the fifth gear or the sixth gear is formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the fifth-sixth gear shift gate  950   d  and the shaft  1  is located at the fifth rotation position R 5 , as illustrated in  FIG. 11C , the reverse engagement portion  6   a  of the reverse fork connection member  6  does not engage with the reverse inner lever er. Therefore, the reverse fork FR is prevented from moving in the axial direction. Accordingly, the reverse gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the reverse shift gate  950   a  and the shaft  1  is located at the reverse rotation position RF, as illustrated in  FIG. 8D , the fork head F 1   d  of the first fork F 1  is located inside the first engagement target portion  41   c  on the further front side than the position where the slit  41   d  of the first main body portion  41  is formed. Therefore, the first fork F 1  is prevented from moving (swinging) in the axial direction. Accordingly, the first gear or the second gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the reverse shift gate  950   a  and the shaft  1  is located at the reverse rotation position RF, as illustrated in  FIG. 9D , the fork head F 2   d  of the second fork F 2  does not engage with the second inner lever e 2 . Then, the fork head F 2   d  is located inside the second engagement target portion  42   b  on the further front side than the position where the slit  42   c  of the second main body portion  42  is formed. Therefore, the second fork F 2  is prevented from moving (swinging) in the axial direction. Accordingly, the third gear or the fourth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the reverse shift gate  950   a  and the shaft  1  is located at the reverse rotation position RF, as illustrated in  FIG. 10D , the fork head F 3   d  of the third fork F 3  does not engage with the third inner lever e 3 . Then, the fork head F 3   d  is located inside the third engagement target portion  42   d  on the further front side than the position where the slit  42   e  of the second main body portion  42  is formed. Therefore, the third fork F 3  is prevented from moving (swinging) in the axial direction. Accordingly, the fifth gear or the sixth gear is not formed in the transmission  100 . 
     In a state where the shift lever  990  is located in the reverse shift gate  950   a  and the shaft  1  is located at the reverse rotation position RF, as illustrated in  FIG. 11D , the reverse engagement portion  6   a  of the reverse fork connection member  6  engages with the reverse inner lever er. Therefore, the reverse fork FR is movable in the axial direction, and the shift lever  990  is moved to the odd number stage side in the shift direction. If the shaft  1  is moved rearward in the axial direction, the reverse fork FR is moved in the axial direction. Accordingly, the reverse gear is formed in the transmission  100 . 
     As can be understood from the above description, the interlock mechanism  10   a  according to the present embodiment has the shaft  1 , the first fork F 1 , the second fork F 2  (third fork F 3 ), the first inner lever e 1 , the second inner lever e 2  (third inner lever e 3 ), and the interlock member  4 . The shaft  1  is movable along the axial direction, and is rotatable in the rotation direction. The first fork F 1  and the second fork F 2  (third fork F 3 ) are disposed to face the shaft  1 . The first inner lever e 1  is disposed in the shaft  1 . In a state where the shaft  1  is located at the first rotation position R 1 , the first inner lever e 1  engages with the first fork F 1 . In a state where the shaft  1  is located at the second rotation position R 2  different from the first rotation position R 1 , the first inner lever e 1  disengages from the first fork F 1 . The second inner lever e 2  (the third inner lever e 3 ) is disposed in the shaft  1 . In a state where the shaft  1  is located at the third rotation position R 3  (fifth rotation position R 5 ) which is the rotated position different from the first rotation position R 1 , the second inner lever e 2  (the third inner lever e 3 ) engages with the second fork F 2  (third fork F 3 ). In a state where the shaft  1  is located at the fourth rotation position R 4  (sixth rotation position R 6 ) different from the third rotation position R 3  (fifth rotation position R 5 ), the second inner lever e 2  (the third inner lever e 3 ) disengages from the second fork F 2  (third fork F 3 ). The interlock member  4  is disposed to be rotatable integrally with the shaft  1  in the rotation direction and to be immovable in the axial direction. In the first fork F 1 , the fork head F 1   d  serving as the first engagement portion engaging with the first inner lever e 1  located at the first rotation position R 1  protrudes. In the second fork F 2  (third fork F 3 ), the fork head F 2   d  (fork head F 3   d ) serving as the second engagement portion engaging with the second inner lever e 2  (third inner lever e 3 ) located at the third rotation position R 3  (fifth rotation position R 5 ) protrudes. The interlock member  4  includes the first main body portion  41  and the second main body portion  42  which are disposed coaxially with the shaft  1  on the outer peripheral side of the shaft  1 , and the connection pin  43  connecting the first main body portion  41  and the second main body portion  42  so as to be integrally rotated in the rotation direction. In the first main body portion  41 , the first engagement target portion  41   c  is cut out which engages with the fork head F 1   d  serving as the first engagement portion in a state where the first main body portion  41  is located at the third rotation position R 3  (fifth rotation position R 5 ). In the second main body portion  42 , the second engagement target portion  42   b  is cut out which engages with the fork head F 2   d  (fork head F 3   d ) serving as the second engagement portion in a state where the second main body portion  42  is located at the first rotation position R 1 . 
     The interlock member  4  includes the first main body portion  41  having the first engagement target portion  41   c  formed therein, the second main body portion  42  having the second engagement target portion  42   b  formed therein, and the connection pin  43  connecting the first main body portion  41  and the second main body portion  42  to each other so that the first main body portion  41  and the second main body portion  42  are integrally rotated in the rotation direction of the shaft  1 . The interlock member  4  configured in this way is disposed coaxially with the outer peripheral side of the shaft  1 . In this simple manner, it is possible to achieve the interlock mechanism  10   a  which engages with and disengages from the fork head F 1   d  of the first fork F 1  and the fork head F 2   d  of the second fork F 2  (fork head F 3   d  of the third fork F 3 ), depending on a position in the rotation direction of the shaft  1 . In this manner, the structure of the interlock mechanism  10   a  is simplified, and the miniaturized interlock mechanism  10   a  can be achieved. As a result, the miniaturized transmission  100  can be achieved. Furthermore, since the structure of the interlock mechanism is simplified, the number of components can be reduced. Therefore, the manufacturing cost of the interlock mechanism  10   a  and the transmission  100  can be reduced. 
     In addition, the interlock mechanism  10   a  can be easily assembled to the shaft  1  by dividing the interlock member  4  into the first main body portion  41  and the second main body portion  42 . Specifically, the interlock member  4  can be assembled to the shaft  1  in a state where the first inner lever e 1  formed integrally with the shift select shaft head  1   a  and the first main body portion  41  are assembled to each other. In addition, the second main body portion  42  can be assembled to the shaft  1  together with the second inner lever e 2  (third inner lever e 3 ). Then, the first main body portion  41  and the second main body portion  42  which are assembled to the shaft  1  are connected to each other by the connection pin  43 . In this manner, the interlock member  4  can be assembled coaxially with the outer peripheral side of the shaft  1 . In this way, the interlock member  4  is divided into the first main body portion  41  and the second main body portion  42 . In this manner, assembly work for the interlock mechanism  10   a  can be facilitated (simplified). Accordingly, assembly workability for the interlock mechanism  10   a  can be improved. As a result, the manufacturing cost of the interlock mechanism  10   a  and the transmission  100  can be reduced. 
     In this case, the interlock member  4  includes the slit  41   d  formed in the first main body portion  41 , and accommodating the first inner lever e 1  so as to be movable in the axial direction of the shaft  1 , the slit  42   c  (slit  42   e ) formed in the second main body portion  42 , and accommodating the second inner lever e 2  (third inner lever e 3 ) so as to be movable in the axial direction of the shaft  1 , the first plate portion  421  formed in an annular shape, allowing the insertion of the shaft  1 , and to be fixed to one end side of the second main body portion  42 , and the second plate portion  422  formed in an annular shape, allowing the insertion of the shaft  1 , and to be fixed to the other end side of the second main body portion  42 . 
     According to this configuration, in a state where the first inner lever e 1  is accommodated in the slit  41   d  of the first main body portion  41 , the first inner lever e 1  (shift select shaft head  1   a ) and the first main body portion  41  can be assembled to the shaft  1 . In addition, in a state where the second inner lever e 2  (third inner lever e 3 ) is accommodated in the slit  42   c  (slit  42   e ) of the second main body portion  42 , the second inner lever e 2  (third inner lever e 3 ) and the second main body portion  42  can be assembled to the shaft  1 . In this case, the shaft  1  can be inserted into the first plate portion  421  and the second plate portion  422 . Accordingly, the second inner lever e 2  (third inner lever e 3 ) and the second main body portion  42  can be very easily assembled so as to be coaxial with the outer peripheral side of the shaft  1 . Therefore, the assembly workability for the interlock mechanism  10   a  can be improved. As a result, the manufacturing cost of the interlock mechanism  10   a  and the transmission  100  can be reduced. 
     In addition, the second main body portion  42  has a semi-cylindrical shape, and the second main body portion  42  is not present below the axis of the communication hole  421   a  of the first plate portion  421  and the communication hole  422   a  of the second plate portion  422 . Therefore, the interlock member  4  and the shaft  1  can be moved close to the second fork F 2  (third fork F 3 ), and thus, the miniaturized transmission  100  can be achieved. 
     (Modification Example of Embodiment) 
     In the above-described embodiment, the second inner lever e 2  and the third inner lever e 3  are fixed to the shaft  1  by using the pin, for example. In addition, the first plate portions  421  and the second plate portion  422  are integrally connected to the second main body portion  42  forming the interlock member  4  by means of welding, for example. 
     In contrast, as illustrated in  FIG. 12 , the second inner lever e 2  and the third inner lever e 3  can be formed integrally with the shaft  1 . Then, after the second inner lever e 2  and the third inner lever e 3  are formed integrally with the shaft  1 , the first plate portion  423  and the second plate portion  424  can be integrated with the second main body portion  42  by means of fitting and welding, for example. Hereinafter, a modification example will be described in detail. The same reference numerals will be given to elements the same as those in the above-described embodiment, and description thereof will be omitted. 
     In this modification example, as illustrated in  FIG. 12 , at least the second inner lever e 2  and the third inner lever e 3  are formed integrally with the shaft  1 . In this case, the second inner lever e 2  and the third inner lever e 3  can be integrally formed by means of electric discharge machining or cutting, for example. Alternatively, the second inner lever e 2  and the third inner lever e 3  which are separately formed in the same manner as the above-described embodiment can be integrated and fixed to the shaft  1  by means of shrinkage fitting. In this modification example, the first inner lever e 1  is also formed integrally with the shift select shaft head  1   a . The shift select shaft head  1   a  is fixed to the shaft  1 . In this manner, the first inner lever e 1  is fixed to the shaft  1 . In addition, in this modification example, the reverse inner lever er is also fixed to the shaft  1  by using the pin, for example. In this case, the reverse inner lever er can be formed integrally with the shaft  1  by means of electric discharge machining or cutting, for example. Alternatively, the reverse inner lever er can be fixed to and integrated with the shaft  1  by means of shrinkage fitting. 
     In this modification example, as illustrated in  FIG. 12 , the second main body portion  42  also has a structure the same as that according to the above-described embodiment. However, in this modification example, a pin engagement portion  42   f  engaging with the connection pin  43  is formed for the second main body portion  42 . Then, in this modification example, the first plate portion  423  and the second plate portion  424  are fixed to the second main body portion  42  so that the second main body portion  42  is coaxial with the outer peripheral side of the shaft  1 . 
     As illustrated in  FIG. 12 , a cutout portion  423   a  is formed in a portion in the circumferential direction of the annular shape of the first plate portion  423 , and the first plate portion  423  is formed in a substantially C-shape. In addition, the first plate portion  423  has a communication hole  423   b  communicating in the forward-rearward direction. Furthermore, as illustrated in  FIG. 13 , the first plate portion  423  has an annular groove portion  423   c  to be fitted to an end portion of the second main body portion  42  having a semi-cylindrical shape. 
     As illustrated in  FIG. 12 , the second plate portion  424  is formed in a substantially annular shape, and has a communication hole  424   a  communicating in the forward-rearward direction. In addition, as illustrated in  FIG. 13 , the second plate portion  424  has an annular groove portion  424   b  to be fitted to an end portion of the second main body portion  42  having a semi-cylindrical shape. 
     In the modification example in which the second inner lever e 2  and the third inner lever e 3  are formed integrally with the shaft  1  in this way, the first plate portion  423  is first inserted into the shaft  1 . In this case, the cutout portion  423   a  is formed in the first plate portion  423 . Accordingly, while a forming position of the cutout portion  423   a  is aligned with a lever portion (projecting portion) of the second inner lever e 2  and the third inner lever e 3 , the first plate portion  423  is inserted until the first plate portion  423  comes into contact with the first main body portion  41 . 
     Next, the second main body portion  42  is assembled to the shaft  1  from the outside in the radial direction of the shaft  1 . In this case, the second main body portion  42  is assembled to the shaft  1  so that the lever portions (projecting portions) of the second inner lever e 2  and the third inner lever e 3  are respectively inserted into the slit  42   c  and the slit  42   e  which are formed in the second main body portion  42 . Then, as illustrated in  FIG. 13 , an end portion of the second main body portion  42  is fitted into the groove portion  423   c  formed in the first plate portion  423 , thereby performing temporary assembling. 
     Subsequently, the second plate portion  424  is inserted into the shaft  1 . Then, as illustrated in  FIG. 13 , an end portion of the second main body portion  42  is fitted into the groove portion  424   b  formed in the second plate portion  424 , thereby performing the temporary assembling. In this way, the first plate portion  423 , the second main body portion  42 , and the second plate portion  424  which are temporarily assembled are integrated with each other in such a manner that the end portions of the second main body portion  42  which are fitted into the groove portion  423   c  and the groove portion  424   b  are welded to each other by means of resistance welding or spot welding, for example. Instead of the case where welding is performed, in the case of adopting the groove portion  423   c  and the groove portion  424   b  each having a barb disposed in advance, the end portion of the second main body portion  42 , the groove portion  423   c,  and the groove portion  424   b  can be mechanically fixed to each other. 
     As can be understood from the above description, in the interlock mechanism  10   a  according to the above-described modification example, the second inner lever e 2  (third inner lever e 3 ) is formed integrally with the shaft  1 . The first plate portion  423  has the cutout portion  423   a  allowing the insertion of the second inner lever e 2  (third inner lever e 3 ) formed integrally with the shaft  1 , in a portion in the circumferential direction of the annular shape. 
     According to this configuration, even in a case where the second inner lever e 2  (third inner lever e 3 ) is formed integrally with the shaft  1 , the cutout portion  423   a  is formed in the first plate portion  423 . Accordingly, the first plate portion  423  can be inserted into the shaft  1 . In this manner, after the first plate portion  423  is inserted, the second main body portion  42  and the second plate portion  424  can be assembled to the shaft  1 . Therefore, the interlock member  4  can be very easily assembled so as to be coaxial with the outer peripheral side of the shaft  1 . 
     Therefore, the assembly workability for the interlock mechanism  10   a  can be improved. As a result, the manufacturing cost of the interlock mechanism  10   a  and the transmission  100  can be reduced. Furthermore, the second inner lever e 2  (third inner lever e 3 ) is formed integrally with the shaft  1 . In this manner, it is not necessary to provide a pin for fixing the second inner lever e 2  (third inner lever e 3 ) to the shaft  1 . Accordingly, the number of components can be reduced. Therefore, the manufacturing cost of the interlock mechanism  10   a  and the transmission  100  can be reduced. 
     The present invention is not limited to the embodiment and the modification example which are described above. Various modification examples can be adopted within the scope of the present invention. 
     For example, in the embodiment and the modification example which are described above, the first fork F 1  to the third fork F 3  are disposed in the housing of the transmission  100  so as to be swingable by the support portion F 1   b  to the support portion F 3   b.  However, even in a case where the first fork F 1  to the third fork F 3  are disposed in the housing of the transmission  100  so as to be movable in the axial direction, the interlock member  4  can restrict the movement of the fork different from the selected fork. Therefore, even in this case, it is possible to expect an advantageous effect the same as that according to the embodiment and the modification example which are described above. 
     In addition, in the embodiment and the modification example which are described above, the fork head F 1   d,  the fork head F 2   d,  and the fork head F 3   d  of the first fork F 1 , the second fork F 2 , and the third fork are configured to protrude. In addition, the first engagement target portion  41   c  of the first main body portion  41 , and the second engagement target portion  42   b  and the third engagement target portion  42   d  of the second main body portion  42  are cut out. In this case, the fork head F 1   d , the fork head F 2   d,  and the fork head F 3   d  can be cut out and formed. The first engagement target portion  41   c,  the second engagement target portion  42   b,  and the third engagement target portion  42   d  can be formed to protrude. In this case, the interlock member  4  can also restrict the movement of the fork different from the selected fork. Therefore, even in this case, it is possible to expect an advantageous effect the same as that according to the embodiment and the modification example which are described above. 
     REFERENCE SIGNS LIST 
       1 : shift select shaft,  2 : shift outer lever,  3 : select outer lever,  4 : interlock member,  41 : first main body portion,  41   c : first engagement target portion,  41   d : slit,  42 : second main body portion,  42   b : second engagement target portion,  42   c : slit,  42   d : third engagement target portion,  42   e : slit,  421 : first plate portion,  422 : second plate portion,  43 : connection pin,  5 : reverse fork shaft,  6 : reverse fork connection member,  10   a : interlock mechanism, e 1 : first inner lever, e 2 : second inner lever, e 3 : third inner lever, F 1 : first fork, F 1   d : fork head (first engagement portion), F 2 : second fork, F 2   d : fork head (second engagement portion), F 3 : third fork, F 3   d : fork head (second engagement portion)