Abstract:
The present invention is a shift device for switching a dog clutch mechanism in a transmission, comprising: a shift shaft capable of moving in an axial direction; a shift member capable of moving in the axial direction within a predetermined waiting stroke range; an elastic member holder for a waiting mechanism; and an elastic member provided in outside of the shift shaft in a radial direction so as to be compressed and expanded between the elastic member holder and the shift member, wherein the elastic member biases the shift member toward one side in the axial direction.

Description:
BACKGROUND OF INVENTION 
     1. Field of the Invention 
     The present invention relates to a shift device for switching a dog clutch mechanism in a transmission. 
     2. Description of the Prior Art 
       FIG. 11  shows a shift device of a gear transmission described in JP Laid-open Publication No. 2006-082737. The shift device includes: a shift shaft  302 , a shift fork  303  fixed to the shift shaft  302  and a shift sleeve  304  engaging with the shift fork  303 . The shift shaft  302  is supported by a transmission case  301  so as to be movable in an axial directional of the shift shaft  302 . A drive pin  308  of the shift fork  303  engages with an inner lever  307  fixed to the lower end portion of a lever shaft  306 . The lever shaft  306  is free-rotatably supported by the transmission case  302 . The lever shaft  306  is connected to a shift lever device through an outer lever  310  and a shift operation force transmission mechanism (not shown). 
     A waiting mechanism includes a coil spring  320  fit onto an outer peripheral surface of the lever shaft  306 . One end part of the coil spring  320  engages with the drive pin  308  and the other end part engages with the lever shaft  306  or the inner lever  307 . Further, a ball type detent mechanism  321  is provided in the shift shaft  302 . 
     According to the configuration of  FIG. 11 , it is required to fit the coil spring  320  onto the outer peripheral surface of the lever shaft  306  before the lever shaft  306  is attached in an inside of the transmission case  301 . Namely, the lever shaft  306  onto which the coil spring  320  has been fit need be attached in the inside of the transmission case  301 , therefore an attachment work takes time and effort. Further, the work of removing the coil spring  320  also takes time and effort. 
     The coil spring  320  is arranged in an upstream of an operation force transmission path relative to the detent mechanism  321 . Thus, a spring load of the coil spring  320  should be set greater than a load with which the detent mechanism  321  holds the shift shaft  302 . Otherwise, the coil spring  320  would be twisted always during a shift operation so that a transmission of the shift operation force would become slow. Further, a configuration that the load is generated by the twist operation of the coil spring  320  causes a size increase in the coil spring  320 . 
       FIG. 12  shows a shift device of a gear transmission described in U.S. Pat. No. 8,276,473. Two shift shafts  402  and  403  are fixed to a transmission case  401  so as not to be able in an axis-directional. Then, shift forks  404 ,  405 , and  406  are fit onto the shift shafts  402  and  403   o  as to be movable in the axial direction. Coil springs  411  and  412  for waiting mechanism are fit onto outer peripheral surfaces of the shift shafts  402  and  403  so as to bias the shift forks  404 ,  405 , and  406  in the axial direction. Further, a shift drum  415  is arranged for driving the shift forks  404 ,  405 , and  406  in the axial direction. Then, a waiting mechanism  416  is arranged in the shift drum  415 . 
     According to the configuration of  FIG. 12 , similarly to the case of  FIG. 11 , it is required to fit the coil springs  411  and  412  onto the outer peripheral surface of the shift shafts  402  and  403  before the shift shafts  402  and  403  are attached in an inside of the transmission case  401 . Namely, the shift shafts  402  and  403  onto which the coil springs  411  and  412  have been fit need be attached in the inside of the transmission case  401 , therefore an attachment work takes time and effort. Further, the work of removing the coil springs  411  and  412  also take time and effort. 
     SUMMARY OF THE INVENTION 
     The present invention has been devised in view of the above-mentioned problems. An object thereof is to provide a shift device in which an arrangement flexibility of an elastic member constituting a waiting mechanism is increased, a work of attaching the elastic member becomes easy, and a compact construction is achievable. 
     In order to resolve the problem, the present invention is a shift device for switching a dog clutch mechanism in a transmission, comprising: a shift shaft arranged so as to be movable in an axial direction of the shift shaft; a shift member fit onto the shift shaft so as to be movable in the axial direction within a predetermined waiting stroke range, the shift member transmitting an axial movement of the shift shaft to an operation member of the dog clutch mechanism; an elastic member holder for a waiting mechanism provided on the shift shaft; and an elastic member arranged outside of the shift shaft in a radial direction of the shift shaft, the elastic member being arrange so as to be compressed and expanded in the axial direction between the elastic member holder and the shift member, and the elastic member biasing the shift member toward one side in the axial direction. 
     According to the present invention, the elastic member for the waiting mechanism is arranged outside in the radial direction of the shift shaft. Thus, an arrangement flexibility of the elastic member is increased and the work of attaching and detaching the elastic member becomes easy. Further, the axial length of the shift shaft can be made compact and hence the entirety of the shift device can also be made compact. 
     In addition to the above-mentioned configuration, the present invention may employ the following configurations. 
     (a) The transmission is composed of a gear transmission, the operation member is composed of a shift sleeve fit onto a speed change shaft provided with the dog clutch mechanism, the shift sleeve is movable in the axial direction, the dog clutch mechanism is constructed such as to switch a power transmitting between the shift sleeve and a change gear of the speed change shaft, and the shift member is composed of a shift fork. 
     According to the above-mentioned configuration (a), in a gear transmission provided with a shift device, compact dimensions are achievable in the shift device. 
     (b) In the transmission employing the above-mentioned configuration (a), the shift shaft is supported by a transmission case, and a detent mechanism for holding the shift shaft at each shift position is provided between the shift shaft and the transmission case. 
     According to the above-mentioned configuration (b), the waiting mechanism provided with the elastic member is arranged in the downstream of the operation force transmission path relative to the detent mechanism. Thus, a position keeping force (an elastic force of the elastic member) of the detent mechanism can be increased without affecting the condition of the waiting operation by the elastic member. That is, even when a pressing force of the detent mechanism is increased, the elastic member for the waiting mechanism is not compressed before the movement of the shift shaft. 
     (c) In the transmission employing the above-mentioned configuration (b), the detent mechanism is arranged in one end portion in the axial direction of the shift shaft, and another detent mechanism is arranged in the other end portion in the axial direction of the shift shaft. 
     According to the above-mentioned configuration (c), the holding force for the shift shaft by the detent mechanism can be made uniform in the axial direction and hence a smooth operation of the shift shaft is ensured. 
     (d) In the transmission employing the above-mentioned configuration (a), the change gear includes a high gear for forward traveling high-speed and a low gear for forward traveling low-speed mutually aligned in the axial direction, the dog clutch mechanism includes a dog clutch mechanism for forward traveling high speed in order to connect between the shift sleeve and the high gear, and a dog clutch mechanism for forward traveling low speed in order to connect between the shift sleeve and the low gear, and the shift position of the shift sleeve is set up in the order of a neutral position, a forward traveling high-speed position, and a forward traveling low-speed position. 
     According to the above-mentioned configuration (d), when a shift is to be performed from the neutral position to the forward traveling high-speed position, in case that a phase of the dog claws of the high-speed gear that is rotation high-speed does not coincide with a phase of the dog claws of the shift sleeve, the shift sleeve is pushed back by a large reaction force from the high-speed gear. However, the reaction force is alleviated by the elastic member of the waiting mechanism. 
     (e) The elastic member holder and the shift member have surfaces opposite to each other in the axial direction, the surfaces are provided with recesses respectively, and both end portions of the elastic member in the axial direction are accommodated in the both recesses. 
     According to the above-mentioned configuration (e), a compact construction is achievable in the axial direction of the waiting mechanism. 
     (f) The elastic member is a coil spring. 
     (g) The elastic member holder and the shift member have stopper surfaces opposite to each other in the axial direction, the stopper surfaces face each other by a distance corresponding to the waiting stroke, and the both stopper surfaces are constructed such as to abut each other before the elastic member is compressed completely. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present invention will be become more apparent from the following description taken in connection with the accompanying drawings, in which: 
         FIG. 1  is a left side view of a utility vehicle including a speed change apparatus according to the present invention; 
         FIG. 2  is a perspective view showing a vehicle body frame and the speed change apparatus of the utility vehicle shown in  FIG. 1 ; 
         FIG. 3  is a longitudinal sectional view of a shift lever device of the utility vehicle shown in  FIG. 1 ; 
         FIG. 4  is a plan view of a shift panel of the shift lever device shown in  FIG. 3 ; 
         FIG. 5  is a partially plan view of the transmission shown in  FIG. 1 ; 
         FIG. 6  is a center longitudinal sectional view (corresponding to a cross section taken along line VI-VI in  FIG. 5 ) of the transmission shown in  FIG. 1 ; 
         FIG. 7  is a sectional view of the transmission shown in  FIG. 6 , taken along line VII-VII; 
         FIG. 8  is a bottom view of the shift shaft shown in  FIG. 6 ; 
         FIG. 9  is a sectional view taken along line IX-IX in  FIG. 8 ; and 
         FIG. 10  shows a modification of the present invention, and is a sectional view of the shift shaft similar to  FIG. 8 ; 
         FIG. 11  is a sectional view of a first conventional example; and 
         FIG. 12  is a sectional view of a second conventional example. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       FIGS. 1 to 9  show a shift device according to the present invention and a utility vehicle including the shift device. Then, an embodiment of the present invention is described below with reference to these drawings. For convenience of description, a forward traveling direction of the utility vehicle will be described as a “front side” of the utility vehicle and respective components, and a left-and-right direction viewed from a driver will be described as a “left-and-right direction” of the utility vehicle and the respective components. 
     In  FIG. 1 , a pair of right and left front wheels  2  is provided in a front portion of a vehicle body frame  1  of the utility vehicle and a pair of right and left rear wheels  3  is provided in a rear portion of the vehicle body frame  1 . A riding space S formed between the front wheels  2  and the rear wheels  3  is surrounded by a ROPS  5 , where the ROPS  5  is an abbreviation of a rollover protective structure. A bench type front seat  6  is arranged in a front half portion of the riding space S and a bench type rear seat  7  is arranged in a rear half portion of the riding space S. A cargo bed  8  is provided on a backward side of the rear seat  7 . A screen  9  is arranged between the bench type rear seat  7  and the cargo bed  8 . A bonnet  13  is provided on a forward side of the riding space S and a dashboard  14  is provided in an upper backward end portion of the bonnet  13 . In the dashboard  14 , a steering wheel device  21  and a shift lever device  22  are provided in a zone where an operation is achievable by the driver sitting in a driver&#39;s region  6   a  of the bench type front seat  6 . 
     An engine  10  is arranged under the rear seat  7  and a gear transmission  11  is arranged on a rear side of the engine  10 . An input shaft  16  of the gear transmission  11  is connected to a crankshaft  15  of the engine  10  through a V-belt type continuously variable transmission  12 . The V-belt type continuously variable transmission  12  is attached such as to extend from a left side surface of the engine  10  to a left side surface of a front portion of the gear transmission  11 . 
     In  FIG. 2 , the vehicle body frame  1  includes a mainframe  1   a  having a rectangular shape elongated in forward and backward directions in plan view, a bonnet frame  1   b  formed in a forward end portion of the mainframe  1   a , and a dashboard frame  1   c  formed in an upper backward end portion of the bonnet frame  1   b . A bracket  23  of the steering wheel device  21  and a bracket  24  of the shift lever device  22  are fixed to the dashboard frame  1   c . In the present embodiment, the driver&#39;s region  6   a  is located in a left end portion of the bench type front seat  6 . Thus, the steering wheel device  21  and the shift lever device  22  are arranged at a forward position relative to the driver&#39;s region  6   a , that is, in a left side portion of the utility vehicle. The gear transmission  11  arranged in a backward end portion of the mainframe  1   a  and the shift lever device  22  attached to the dashboard frame  1   c  are connected to each other through a push-pull type cable mechanism  25  so as to transmit a shift operation force. The push-pull cable mechanism  25  serves as an example of an operation force transmission mechanism described in the claims of the present application, and extends downward from the shift lever device  22 , then reaches the forward end portion of the mainframe  1   a , then extends right backward on the mainframe  1   a  approximately along a propeller shaft  27  for front wheels, and then reaches an upper portion of the gear transmission  11 . 
     In  FIG. 3 , the shift lever device  22  includes a shift lever  31 , a shift panel  32 , and a third detent mechanism  33  (first and second detent mechanisms are described later). The shift lever  31  is supported by the bracket  24  fixed to the dashboard frame  1   c  through a pivot  34  so as to be turnable or rotatable around the pivot  34 . The shift lever  31  passes through a shift slot  32   a  of the shift panel  32  and then protrudes upper backward. A lower end portion  31   a  of the shift lever  31  protrudes forward. Further, a forward end of the lower end portion  31   a  is connected to an inner cable  25   a  of the push-pull cable mechanism  25 . The inner cable  25   a  is inserted into an outer cable  25   b  and then extends downward together with the outer cable  25   b . The third detent mechanism  33  includes a recess-formed member  35  provided in the shift lever  31 , a third detent spring  37  arranged in the bracket  24 , and a third detent ball  36  pressed against the recess-formed member  35  by the third detent spring  37 . 
     In  FIG. 4 , the shift slot  32   a  is formed in a straight line shape extending from an upper forward end portion of the shift panel  32  to a lower backward end portion thereof. Then, the shift lever  31  moves in a straight line in an inside of the shift slot  32   a  so that four shift positions are switched. The four shift positions are, in the order from the upper forward end to the lower backward end, a forward traveling low-speed position (L), a forward traveling high-speed position (H), a neutral position (N), and a reverse position (R). 
     In  FIG. 5 , a backward end portion of the inner cable  25   a  of the push-pull cable mechanism  25  is connected to an outer lever  41  arranged above a transmission case  11   a . The outer lever  41  is fixed to an upper end portion of the lever shaft  42  extending approximately vertically. 
     In  FIG. 6 , the lever shaft  42  is arranged in an approximately center portion in forward and backward directions of the transmission case  11   a , then passes through an upper wall boss portion  11   b  of the transmission case  11   a  in up and down directions, and then is free-rotatably supported by the upper wall boss portion  11   b . The inner lever  43  arranged in the transmission case  11   a  is fixed to the lower end portion of the lever shaft  42 , and then extends forward in an approximately horizontal direction from the lever shaft  42 , and then reaches a space under the shift shaft  50 . 
     The shift shaft  50  serves an example of the movable member of the shift mechanism described in the claims of the present application, and is arranged on a forward side of the lever shaft  42  and extends in the right and left directions. 
     In a space on the forward side of the shift shaft  50 , the input shaft  16  of the gear transmission  11 , a counter shaft  62 , a reverse idler shaft  63 , and an output shaft  64  for front wheels are arranged approximately in parallel to the shift shaft  50 . The input shaft  16  is arranged in an upper forward end of the transmission case  11   a , the counter shaft  62  is arranged on a backward side of the input shaft  16 , and the reverse idler shaft  63  is arranged in an under space between the input shaft  16  and the counter shaft  62 . The output shaft  64  for front wheels is arranged under the counter shaft  62 , and is connected to the propeller shaft  27  for front wheels ( FIG. 2 ) through a two-wheel drive to four-wheel drive switching mechanism (not shown), so as to transmit a rotation power. 
     An intermediate output shaft  65  for rear wheels and a drive shaft  66  for rear wheels are arranged in a space on a backward side of the shift shaft  50 . The drive shaft  66  is connected to the counter shaft  62  through a differential mechanism  67 , a gear  68  of the intermediate output shaft  65  for rear wheels and a gear  69  of the output shaft  64  for front wheels, so as to transmit the rotation power. 
       FIG. 8  is a bottom view of the shift shaft  50 , where the shift fork  51  is fit on an outer peripheral surface of the shift shaft  50  within a range of a predetermined stroke S 1  in the axial direction so as to be movable in the axial direction. The shift fork  51  serves as an example of the shift member described in the claims of the present application, and is connected to the inner lever  43  of the lever shaft  42  through a waiting mechanism  40  so as to transmit the shift operation force. 
     The waiting mechanism  40  includes a spring holder  45  arranged on a left side (in an arrow A4b direction side) of the shift fork  51  with a predetermined stroke S 1  in between, and a coil spring  46  provided between the spring holder  45  and the shift fork  51  so as to be compressible and extendable in the axial direction. The coil spring  46  is arranged on a forward side of the shift shaft  50 . The coil spring  46  serves as an example of the elastic member described in the claims of the present application, and the spring receiver holder  45  serves as an example of the elastic member holder described in the claims of the present application. An engagement groove  47  extending in the forward and backward directions is formed in a lower surface of the spring holder  45 . Then, a backward end of the engagement groove  47  is opened. A forward end portion of the inner lever  43  fixed to the lower end portion of the lever shaft  42  is provided with an engaging pin  44 . The engaging pin  44  engages with the engagement groove  47  so as to movable forward and backward. 
       FIG. 9  is a sectional view taken along line IX-IX in  FIG. 8 , where the engaging pin  44  of the inner lever  43  protrudes upward and then engages with the engagement groove  47  of the spring holder  45  from below. 
     In  FIG. 7 , the shift shaft  50  is supported by a right support boss  11   c  formed in a right side wall of the transmission case  11   a  and a left support boss  11   d  formed in a left side wall of the transmission case  11   a  so as to be slidable in the axial direction 
     The waiting mechanism  40  is described below in detail. Amount of leftward relative movement of the shift fork  51  relative to the shift shaft  50  is restricted by a right end surface  45   b  of the spring holder  45 . Further, Amount of rightward relative movement of the shift fork  51  relative to the shift shaft  50  is restricted by an annular stopper  53  formed in the outer peripheral surface of the shift shaft  50 . The spring holder  45  is provided with a forward projection portion protruding forward from the shift shaft  50 . Then, in a right end surface of the forward projection portion, a cylindrical recess  45   a  into which a left side portion of the coil spring  46  is inserted is formed. On the other hand, in a left end surface of the shift fork  51  protruding forward from the shift shaft  50 , a cylindrical recess  51   a  for accommodating a right end portion of the coil spring  46  is formed. That is, both of the right and the left end portions of the coil spring  46  are inserted into and supported by the recess  45   a  of the spring holder  45  and the recess  51   a  of the shift fork  51 . 
       FIG. 7  shows a neutral state that a shift operation is not yet performed. In this state, the shift fork  51  is pressed or pushed rightward by the coil spring  46  and a right end surface of the shift fork  51  abuts against the stopper  53 . 
     When the shift shaft  50  and the spring holder  45  move integrally rightward, the shift fork  51  also moves rightward with the coil spring  46  in between. When a resistance force in the axial direction acting on the shift fork  51  from a shift sleeve  90  (described later) increases to a predetermined value or higher, the spring holder  45  and the shift shaft  50  move rightward relatively to the shift fork  51  so as to compress the coil spring  46 . When the coil spring  46  is compressed by the predetermined stroke S 1 , the right end surface  45   b  of the spring holder  45  abuts against the left end surface of the shift fork  51 . On the contrary, when the shift shaft  50  and the spring holder  45  move leftward, the shift fork  51  moves leftward with the stopper  53  in between. 
     A structure of the gear transmission  11  is briefly described below. In  FIG. 7 , both ends in the axial direction of the counter shaft  62  are free-rotatably supported by the transmission case  11   a  through bearings  71  in between. In a right end portion of the counter shaft  62 , a counter low gear  72  for forward traveling low-speed and a counter high gear  73  for forward traveling high-speed are arranged in the order from right to left. Then, in the left end portion of the counter shaft  62 , an output gear  75  and a counter reverse gear  76  are arranged in the order from left to right. The output gear  75  is formed integrally with the counter shaft  62 . The counter reverse gear  76  is fit onto the counter shaft  62  so as to be free-rotatable around the counter shaft  62  and not to be movable in the axial direction. 
     The counter low gear  72  is spline-fit onto an outer peripheral surface of a boss member  78  so as to rotate integrally with the boss member  78  . . . . The boss portion  78  is formed separately from the counter low gear  72 . The counter high gear  73  is fit onto the outer peripheral surface of the boss member  78  with a needle bearing  80  in between so as to be free-rotatable relative to the boss portion  78 . The boss member  78  is fit onto the outer peripheral surface of the counter shaft  62  with a pair of needle bearings  81  in between so as to be free-rotatable relative to the counter shaft  62 . A left end portion of the boss member  78  is provided with low-speed dog claws  83  and the counter high gear  73  is provided with high-speed dog claws  84 . The high-speed dog claws  84  extend leftward beyond the low-speed dog claws  83 . The counter reverse gear  76  is provided with reverse dog claws  86 . 
     The counter low gear  72  and the counter high gear  73  engage respectively with an input low gear  93  and an input high gear  94 . Further, the counter reverse gear  76  engages with an idle reverse gear  95  and the output gear  75  engages with a second output gear  96 . 
     The input low gear  93  and the input high gear  94  are arranged on the input shaft  16  shown in  FIG. 6 . The idle reverse gear  95  is fit onto the reverse idler shaft  63  and engages with the input reverse gear  97  of the input shaft  16 . 
     Returning to  FIG. 7 , the shift sleeve  90  of the above-mentioned shift mechanism is spline-fit onto a center portion in the axial direction of the counter shaft  62  between the counter high gear  73  and the counter reverse gear  76  so as to be movable in the axial directional. The shift sleeve  90  serves as an example of the movable member described in the claims of the present application, and is provided with forward traveling dog claws  85  integrally formed at a right end, backward traveling dog claws  87  integrally formed at a left end, and an outer periphery circular groove  90   a  formed in a center portion such as to be engaged with a two-pronged portion of the shift fork  51 . A dog clutch mechanism Ch for forward traveling high-speed is constituted by the forward traveling dog claws  85  of the shift sleeve  90  and the high-speed dog claws  84  of the counter high gear  73 . A dog clutch mechanism Cl for forward traveling low-speed is constituted by the forward traveling dog claws  85  of the shift sleeve  90  and the low-speed dog claws  83  of the counter low gear  72 . A dog clutch mechanism Cr for backward traveling is constituted by the reverse dog claws  87  of the shift sleeve  90  and the reverse dog claws  86  of the reverse gear  76 . Since the two-pronged portion of the shift fork  51  engages with the outer periphery circular groove  90   a , a rotation of the shift fork  51  about the shift shaft  50  is avoided. 
       FIG. 7  shows a situation that the shift sleeve  90  is at a neutral position. When the shift sleeve  90  moves rightward (in an arrow A4a direction) from the neutral position, first, the forward traveling dog claws  85  of the shift sleeve  90  engage with the high-speed dog claws  84  of the counter high gear  73  so that the dog clutch mechanism Ch for forward traveling high-speed becomes in engagement state. Namely, the gear transmission  11  goes into the forward traveling high-speed state. Further, when the shift sleeve  90  moves in the arrow A4a direction, the forward traveling dog claws  85  of the shift sleeve  90  pass a neutral state and then engage with the low-speed dog claws  83  of the boss member  78  so that the dog clutch mechanism Cl for forward traveling low-speed becomes in engagement state. Namely, the gear transmission  11  goes into the forward traveling low-speed state. On the contrary, when the shift sleeve  90  moves leftward (in an arrow A4b direction) from the neutral position, the backward traveling dog claws  87  of the shift sleeve  90  engage with the reverse dog claws  86  of the counter reverse gear  76  so that the dog clutch mechanism Cr for backward traveling becomes in engagement state. Namely, the gear transmission  11  goes into the backward traveling state. 
     As described above, the shift device includes the shift shaft  50 , the shift fork  51 , the waiting mechanism  40 , and the shift sleeve  90  and further includes a first detent mechanism  100  formed in a right side portion in the axial direction of the shift shaft  50  and a second detent mechanism  200  formed in a left side portion of the shift shaft  50 . In the shift shaft  50 , a rotation of the shift shaft  50  is prevented by pressing a force of the two detent mechanisms  100  and  200  and by a resistance force of the shift fork  51  engaging in the rotation direction with the coil spring  46  in between. 
     The first and the second detent mechanisms  100  and  200  are described below. The first detent mechanism  100  on the right side includes four detent recesses  101 ,  102 ,  103 , and  104  formed in an upper end surface of the shift shaft  50 , a first detent ball  110  arranged on the upper surface of the shift shaft  50 , and a first detent spring  111  for pressing the first detent ball  110  against the upper surface of the shift shaft  50 . The first detent ball  110  serves as an example of the detent member described in the claims of the present application. Further, the first detent spring  111  serves as an example of the elastic member described in the claims of the present application. 
     The first detent spring  111  is arranged in an inside of a first spring case  115 . The first spring case  115  is inserted and screwed from above into a female screw hole  116  formed in the right support boss  11   c . A lower end of the first spring case  115  is opened from above into an inner space of the right support boss  11   c . An upper end of the first detent spring  111  abuts against an upper wall of the first spring case  115  and a lower end of the first detent spring  111  abuts against a first push rod  117  so as to press the push rod  117  downward. The first detent ball  110  is located in the lower end opening portion in the inside of the first spring case  115  and abuts against a lower end surface of the push rod  117  so as to be biased downward by the first detent spring  111  with the push rod  117  in between and engage selectively with the four detent recesses  101 ,  102 ,  103 , and  104 . 
     The four detent recesses  101 ,  102 ,  103 , and  104  are, in the order from right to left, a reverse detent recess  101 , a neutral detent recess  102 , a high detent recess  103  for forward traveling high-speed, and a low detent recess  104  for forward traveling low-speed. The four detent recesses  101 ,  102 ,  103 , and  104  are each formed in the shape of a partially spherical surface approximately corresponding to an outer peripheral surface shape of the first detent ball  111 . However, the reverse detent recess  101  on the rightmost side is extended rightward in the axial direction by a little amount and the reverse detent recess  104  on the leftmost side is extended leftward in the axial direction by a little amount. 
     Further, in the upper end surface of the shift shaft  50 , a protrusion  120  for neutral detection is formed at a position on the right side of reverse detent recess  101 . On the other hand, the right support boss  11   c  is provided with a neutral position detector  121 . When the shift shaft  50  is at the neutral position, the protrusion  120  goes into contact with a lower-end detection rod  121   a  of the neutral position detector  121 . The neutral position detector  121  is electrically connected to a meter device (not shown) and then turns ON a neutral indicator of the meter device when the protrusion  120  is detected. 
     The second detent mechanism  200  on the left side includes four detent recesses  201 ,  202 ,  203 , and  204  formed in the upper end surface of the shift shaft  50 , a second detent ball  210  arranged on the upper end surface of the shift shaft  50 , and a second detent spring  211  for pressing the second detent ball  210  against the upper surface of the shift shaft  50 . 
     The basic configuration of the second detent mechanism  200  is similar to that of the first detent mechanism  100 . However, a diameter of the second detent ball  210  is greater than a diameter of the first detent ball  110  and a wire diameter and a coil diameter of the second detent spring  211  are greater than a wire diameter and a coil diameter of the first detent spring  111 . That is, the second detent mechanism  200  has a larger spring load (pressing load) than the first detent mechanism  100 . 
     The second detent spring  211  is arranged in an inside of a second spring case  215 . Then, the second spring case  215  is inserted and screwed from above into a female screw hole  216  formed in the left support boss  11   d . A lower end of the second spring case  215  is opened from above into an inner space of the left support boss  11   d . An upper end of the second detent spring  211  abuts against an upper wall of the second spring case  215  and a lower end of the second detent spring  211  abuts against the upper end of detent ball  210 . The second detent ball  210  is located in a lower end opening portion in the inside of the second spring case  215  and engages selectively with the four detent recesses  201 ,  202 ,  203 , and  204 . 
     The four detent recesses  201 ,  202 ,  203 , and  204  are, in the order from right to left, a reverse detent recess  201 , a neutral detent recess  202 , a high detent recess  203  for forward traveling high-speed, and a low detent recess  204  for forward traveling low-speed. 
     Among the four detent recesses  201 ,  202 ,  203 , and  204 , the neutral detent recess  202  is smaller than the other three detent recesses  201 ,  203 , and  204  and located above them. Further, the neutral detent recess  202  has a shape of a partially spherical surface corresponding to an outer peripheral surface of the second detent ball  210 . In the reverse detent recess  201 , the high detent recess  203 , and the low detent recess  204 , each lower end has the shape of a partially spherical surface corresponding to an outer peripheral surface shape of the second detent ball  210 . However, a flat inclined surface of weak inclination is formed in a left side portion of the reverse detent recess  201 , a left side portion and a right side portion of the high detent recess  203 , and a right side portion of the low detent recess  204 . The reason why the neutral detent recess  202  is formed such as to have a smaller area and a higher bottom position than the other detent recesses  201 ,  203 , and  204  as described above is that at the neutral position, no dog claws engage with each other and hence positioning does not require a large load. 
     Further, a protrusion  123  for reverse detection is formed in an upper end portion of the spring holder  45  of the waiting mechanism  40 . On the other hand, the left support boss  11   d  is provided with a reverse position detector  124 . When the shift shaft  50  is at the reverse position, the protrusion  123  goes into contact with a lower-end detection rod  124   a  of the reverse position detector  124 . The reverse position detector  124  is electrically connected to a meter device (not shown) and then turns ON a reverse indicator of the meter device when the protrusion  123  is detected. 
     The shift operation is described below. 
     [Shift from Neutral State to Forward Traveling High-Speed State] 
     (1) In  FIG. 1 , during the time that the vehicle is traveling or stopping, the driver sitting in the driver&#39;s region  6   a  grips a knob in the upper end portion of the shift lever  31  with his/her right hand and operates the shift lever  31 . That is, the shift lever  31  at the neutral position (N) shown in  FIG. 4  is turned or moved to the forward traveling high-speed position (H). 
     (2) In  FIG. 3 , when the shift lever  31  is turned in an arrow Ala direction from the neutral position (N) to the forward traveling high-speed position (H), the inner cable  25   a  of the cable mechanism  25  is pushed down in an arrow A2a direction (downward) in the inside of the outer cable  25   b.    
     (3) In  FIG. 5 , in association with the movement of the inner cable  25   a  in the arrow A2a direction, the outer lever  41  and the lever shaft  42  are turned or rotated about an axis of the lever shaft  42  in an arrow A3a direction. 
     (4) In  FIG. 8 , the inner lever  43  is turned integrally with the lever shaft  42  in the arrow A3a direction. In association with this, the shift shaft  50  and the spring holder  45  move integrally in the arrow A4a direction (rightward) by virtue of the engaging pin  44  and the edge of the engagement groove  47 . 
     (5) In  FIG. 7 , when the shift shaft  50  and the spring holder  45  move in the arrow A4a direction (rightward), the shift fork  51  also moves in the arrow A4a direction with the coil spring  46  in between. 
     (6) In association with the movement of the shift shaft  50  in the arrow A4a direction, the first detent ball  110  and the second detent ball  210  escape upward from the neutral detent recesses  102  and  202 , respectively. 
     (7) When the shift shaft  50 , the spring holder  45 , the shift fork  51 , and the shift sleeve  90  move in the arrow A4a direction from the neutral position to the forward traveling high-speed position, the forward traveling dog claws  85  of the shift sleeve  90  engage with the high-speed dog claws  84  of the counter high gear  73 . Namely, the dog clutch mechanism Ch for forward traveling high-speed becomes in engagement state. Almost at the same time of this, the first detent ball  110  and the second detent ball  210  engage respectively with the high detent recesses  103  and  203 . 
     (8) In the course that the shift sleeve  90  moves from the neutral position to the forward traveling high-speed position, in some cases, the forward traveling dog claws  85  of the shift sleeve  90  abut against left end surfaces in the axial direction of the high-speed dog claws  84  of the counter high gear  73  so that the dog claws  85  and  84  do not engaged with each other. In such cases, the waiting mechanism  40  acts. That is, when the forward traveling dog claws  85  of the shift sleeve  90  abut against the left end surface of the high-speed dog claws  84  of the counter high gear  73 , after that, the shift shaft  50  and the spring holder  45  move further in the arrow A4a direction relative to the shift sleeve  90  and the shift fork  51  which are stopping. As a result, the coil spring  46  is compressed so that energy is stored into the coil spring  46  and, at the same time, the first detent ball  110  and the second detent ball  210  engage respectively with the high detent recesses  103  and  203  for forward traveling high-speed. 
     (9) After that, in association with a relative rotation of the counter shaft  62  and the shift sleeve  90  relative to the counter high gear  73 , when a phase of the forward traveling dog claws  85  of the shift sleeve  90  and a phase of the high-speed dog claws  84  of the counter high gear  73  go into agreement with each other, the coil spring  46  expands. Then, in association with the expansion of the coil spring  46 , the shift fork  51  and the shift sleeve  90  move in the arrow A4a direction so that the forward traveling dog claws  85  of the shift sleeve  90  engage with the high-speed dog claws  84  of the counter high gear  73 . Namely, the dog clutch mechanism Ch for forward traveling high-speed becomes in engagement state. 
     (10) In the forward traveling low-speed state of the gear transmission  11 , the first and the second detent balls  110  and  210  engage respectively with the high detent recesses  1 . 03  and  203  for forward traveling high-speed so as to be positioned and held. 
     (11) In the above-mentioned shift operation, in addition to the role of positioning and holding the shift shaft  50  at the forward traveling high-speed position, the second detent mechanism  200  plays also a role of smoothly guiding and pulling the shift shaft  50  into the forward traveling high-speed position. That is, at an early stage that the second detent ball  210  enters the high detent recess  203 , the second detent ball  210  is smoothly guided and pulled to a deep bottom of the high detent recess  203  by the flat inclined surface on the right side of the high detent recess  203 . Then, at last, when the first and the second detent balls  110  and  210  both engage with the high detent recesses  103  and  203 , total of the spring loads (the pressing loads) of the detent springs  111  and  211  causes the shift shaft  50  to be held at the forward traveling high-speed position. 
     [Shift from Forward Traveling High-Speed State to Forward Traveling Low-Speed State] 
     (1) In  FIG. 4 , the shift lever  31  is turned upward further from the forward traveling high-speed position (H) to the forward traveling low-speed position (L). An action for transmitting the shift operation force from the shift lever  31  to the shift shaft  50  shown in  FIG. 7  is similar to an action at the time of shift from the above-mentioned neutral position to the forward traveling high-speed position. Thus, description is omitted. 
     (2) In  FIG. 7 , when the shift shaft  50  and the spring holder  45  move further in the arrow A4a direction from the forward traveling high-speed position, the shift fork  51  also moves further in the arrow A4a direction with the coil spring  46  in between. 
     (3) In association with the movement of the shift shaft  50  in the arrow A4a direction, the first detent ball  110  and the second detent ball  210  escape upward from the high detent recesses  103  and  203  for forward traveling high-speed, respectively. 
     (4) When the shift shaft  50 , the spring holder  45 , the shift fork  51 , and the shift sleeve  90  move in the arrow A4a direction from the forward traveling high-speed position to the forward traveling low-speed position, the forward traveling dog claws  85  of the shift sleeve  90  escape from the high-speed dog claws  84  of the counter high gear  73 , then pass the neutral state, and then engage with the low-speed dog claws  83  of the counter low gear  72 . Namely, the dog clutch mechanism Cl for forward traveling low-speed becomes in engagement state. At approximately the same time as this, the first detent ball  110  and the second detent ball  210  engage respectively with the low detent recesses  104  and  204 . 
     (5) In the course that the shift sleeve  90  moves from the forward traveling high-speed position to the forward traveling low-speed position, in some cases, the forward traveling dog claws  85  of the shift sleeve  90  abut against a left end surface of the low-speed dog claws  83  of the counter low gear  72  so that the dog claws  85  and  83  do not engaged with each other. Also in such cases, the waiting mechanism  40  acts. That is, after the forward traveling dog claws  85  of the shift sleeve  90  abut against the left end surface of the low-speed dog claws  83  of the counter low gear  72 , the shift shaft  50  and the spring holder  45  move further in the arrow A4a direction relative to the shift sleeve  90  and the shift fork  51  which are stopping. As a result, the coil spring  46  is compressed so that energy is stored into the coil spring  46  and, at the same time, the first detent ball  110  and the second detent ball  210  engage respectively with the low detent recesses  104  and  204  for forward traveling low-speed. 
     (6) After that, in association with the relative rotation of the counter shaft  62  and the shift sleeve  90  relative to the counter low gear  72 , when the phase of the forward traveling dog claws  85  of the shift sleeve  90  and a phase of the low-speed dog claws  83  of the counter low gear  72  go into agreement with each other, the coil spring  46  expands. Then, in association with the expansion of the coil spring  46 , the shift fork  51  and the shift sleeve  90  move in the arrow A4a direction so that the forward traveling dog claws  85  of the shift sleeve  90  engage with the low-speed dog claws  83  of the counter low gear  72 . Namely, the dog clutch mechanism Cl for forward traveling low-speed becomes in engagement state. 
     (7) In the forward traveling low-speed state of the gear transmission  11 , the first and the second detent balls  110  and  210  engage respectively with the low detent recesses  104  and  204  for forward traveling low-speed so as to be positioned and held. 
     (8) In the above-mentioned shift operation, in addition to the role of positioning and holding the shift shaft  50  at the forward traveling low-speed position, similarly to the above-mentioned shift action to the forward traveling high-speed position, the second detent mechanism  200  plays also the role of smoothly guiding and pulling the shift shaft  50  into the forward traveling low-speed position by using the flat inclined surface formed in the right side portion of the low detent recess  204  of the second detent mechanism  200 . Further, also at the time that the second detent ball  210  escapes from the high detent recess  203  for forward traveling high-speed, the second detent ball  210  smoothly escapes from the high detent recess  203  by virtue of the flat inclined surface formed in the left side of the high detent recess  203 . 
     That is, despite that both side portions of the shift shaft  50  are pressed by the first and the second detent balls  110  and  210 , the first and the second detent balls  110  and  210  smoothly escape from the high detent recesses  103  and  203  and smoothly engage with the low detent recesses  104  and  204 . 
     (9) Further, in the first detent mechanism  100 , the left end of the low detent recess  104  is slightly extended leftward in the axial direction. Thus, in the forward traveling low-speed position, an overstroke of the shift shaft  50  is ensured. 
     That is, in a configuration that the push-pull cable mechanism  25  is employed as the operation force transmission mechanism, in some cases, the stroke of the shift lever operation is not sufficiently transmitted to the shift shaft  50 . In such cases, the shift shaft  50  is caused to exceed the regular forward traveling low-speed position in the rightward direction so that complete engagement between the forward traveling dog claws  85  of the shift sleeve  90  and the low-speed dog claws  83  of the counter low gear  72  is ensured. 
     [Shift from Forward Traveling High-Speed State to Neutral State] 
     (1) In  FIG. 4 , the shift lever  31  is turned or moved downward from the forward traveling high-speed position (H) to the neutral position (N). 
     (2) In  FIG. 3 , when the shift lever  31  is turned in an arrow A1b direction from the forward traveling high-speed position (H) to the neutral position (N), the inner cable  25   a  of the cable mechanism  25  is pushed up in an arrow A2b direction (upward) in the inside of the outer cable  25   b.    
     (3) In  FIG. 5 , in association with the movement of the inner cable  25   a  in the arrow A2b direction, the outer lever  41  and the lever shaft  42  are rotated about the lever shaft axis in an arrow A3b direction. 
     (4) In  FIG. 8 , the inner lever  43  is turned integrally with the lever shaft  42  in the arrow A3b direction. In association with this, the shift shaft  50  and the spring holder  45  move in the arrow A4b direction (leftward) by virtue of the engaging pin  44  and the edge of the engagement groove  47 . 
     (5) When the shift shaft  50  and the spring holder  45  move in the arrow A4b direction from the forward traveling high-speed position, the shift fork  51  also moves further in the arrow A4b direction of from the forward traveling high-speed position with the annular stopper  53  in between. 
     (6) In  FIG. 7 , in association with the movement of the shift shaft  50  in the arrow A4b direction (leftward), the first detent ball  110  and the second detent ball  210  escape upward from the high detent recesses  103  and  203 , respectively. In this case, the second detent ball  210  can escape smoothly by virtue of being guided by the flat inclined surface on the right side of the high detent recess  203  for forward traveling high-speed. 
     (7) When the shift shaft  50 , the spring holder  45 , the shift fork  51 , and the shift sleeve  90  move in the arrow A4b direction from the forward traveling high-speed position to the neutral position, the forward traveling dog claws  85  of the shift sleeve  90  escape from the high-speed dog claws  84  of the counter high gear  73 . Namely, the dog clutch mechanism Ch for forward traveling high-speed becomes in disengagement state. After that, the first detent ball  110  and the second detent ball  210  engage respectively with the neutral recesses  102  and  202 . 
     [Shift from Forward Traveling Low-Speed State to Neutral State] 
     In  FIG. 4 , the shift lever  31  is turned or moved downward from the forward traveling low-speed position (L) through the forward traveling high-speed position (H) to the neutral position (N). The action for transmitting the shift operation force from the shift lever  31  to the shift shaft  50  shown in  FIG. 7  and the action of the shift mechanism are basically similar to the action at the time of above-mentioned shift from the forward traveling high-speed position to the neutral position. 
     [Shift from Neutral State to Backward Traveling State] 
     (1) In  FIG. 4 , during the time that the vehicle is stopping, the driver turns the shift lever  31  downward from the neutral position (N) to the reverse position (R). 
     (2) In  FIG. 3 , when the shift lever  31  is turned in the arrow A1b direction from the neutral position (N) to the reverse position (R), the inner cable  25   a  of the push-pull cable mechanism  25  is pushed up in the arrow A2b direction (upward) in the inside of the outer cable  25   b.    
     (3) In  FIG. 5 , in association with the movement of the inner cable  25   a  in the arrow A2b direction, the outer lever  41  and the lever shaft  42  are turned or rotated about the lever shaft axis in the arrow A3b direction. 
     (4) In  FIG. 8 , the inner lever  43  is turned integrally with the lever shaft  42  in the arrow A3b direction. In association with this, the shift shaft  50  and the spring holder  45  move integrally in the arrow A4b direction (leftward) by virtue of the engaging pin  44  and the edge of the engagement groove  47 . 
     (5) In  FIG. 7 , when the shift shaft  50  and the spring holder  45  move in the arrow A4b direction (leftward), the shift fork  51  also moves in the arrow A4b direction with the stopper  53  in between. 
     (6) In association with the movement of the shift shaft  50  in the arrow A4b direction, the first detent ball  110  and the second detent ball  210  escape upward from the neutral detent recesses  102  and  202 , respectively. 
     (7) When the shift shaft  50 , the spring holder  45 , the shift fork  51 , and the shift sleeve  90  move in the arrow A4b direction from the neutral position to the reverse position, the reverse dog claws  87  of the shift sleeve  90  engage with the reverse dog claws  86  of the counter reverse gear  76 . Namely, the dog clutch mechanism Cr for backward traveling becomes in engagement state. Almost at the same time of this, the first detent ball  110  and the second detent ball  210  engage respectively with the reverse detent recesses  101  and  201 . 
     (8) In the reverse state of the gear transmission  11 , the first and the second detent balls  110  and  210  engage respectively with the reverse detent recesses  101  and  201  so as to be positioned and held. 
     (9) Further, in addition to the role of positioning and holding the shift shaft  50  at the reverse position, the second detent mechanism  200  plays also the role of smoothly guiding and pulling the shift shaft  50  into the reverse position. That is, at an early stage that the second detent ball  210  enters the reverse detent recess  201 , the second detent ball  210  is smoothly guided and pulled to the deep bottom of the reverse detent recess  201  by the flat inclined surface on the left side of the reverse detent recess  201 . Then, at last, when the first and the second detent balls  110  and  210  both engage with the reverse detent recesses  101  and  201 , total of the spring loads (the pressing loads) of the detent springs  111  and  211  causes the shift shaft  50  to be held at the reverse position. 
     [Shift from Backward Traveling State to Neutral State] 
     (1) In  FIG. 4 , the shift lever  31  is turned from the reverse position (R) to the neutral position (N). 
     (2) In  FIG. 3 , when the shift lever  31  is turned in the arrow Ala direction from the reverse position (R) to the neutral position (N), the inner cable  25   a  of the cable mechanism  25  is pushed down in the arrow A2a direction of (downward) in the inside of the outer cable  25   b.    
     (3) In  FIG. 5 , in association with the movement of the inner cable  25   a  in the arrow A2a direction, the outer lever  41  and the lever shaft  42  are turned or rotated about the lever shaft axis in the arrow A3a direction. 
     (4) In  FIG. 8 , the inner lever  43  is turned integrally with the lever shaft  42  in the arrow A3a direction. In association with this, the shift shaft  50  and the spring holder  45  move in the arrow A4a direction (rightward) by virtue of the engaging pin  44  and the edge of the engagement groove  47 . 
     (5) When the shift shaft  50  and the spring holder  45  move in the arrow A4a direction from the reverse position, the shift fork  51  also moves in the arrow A4a direction from the reverse position with the coil spring  46  in between. 
     (6) In association with the movement of the shift shaft  50  in the arrow A4a direction, the first detent ball  110  and the second detent ball  210  escape respectively from the reverse detent recesses  101  and  201 . 
     (7) When the shift shaft  50 , the spring holder  45 , the shift fork  51 , and the shift sleeve  90  move in the arrow A4a direction from the reverse position to the neutral position, the reverse dog claws  87  of the shift sleeve  90  escape from the reverse dog claws  86  of the counter reverse gear  76 . Namely, the dog clutch mechanism Cr for backward traveling becomes in disengagement state. Then, the first detent ball  110  and the second detent ball  210  return respectively to the neutral recesses  102  and  202 . 
     In the reverse shift operation, the waiting operation by the waiting mechanism  40  has an effect at the time of return from the reverse position to the neutral position. 
     Effects of the Embodiment 
     (1) Instead of being fit onto the outer peripheral surface of the shift shaft  50 , the coil spring  46  for the waiting mechanism is arranged at a position distant from the shift shaft  50  in the forward direction. Thus, an arrangement flexibility of the coil spring  46  is increased and a work of attaching and detaching the coil spring  46  becomes easy. Further, the axial length of the shift shaft  50  can be made compact and hence the entirety of the shift device can also be made compact. 
     (2) The detent mechanisms  100  and  200  are provided between the shift shaft  50  and the transmission case  1   a . Thus, the waiting mechanism  40  is located in a downstream of the operation force transmission path relative to the detent mechanisms  100  and  200 . Accordingly, the position keeping force of the detent mechanisms  100  and  200  can be increased without affecting the condition of the waiting operation by the coil spring  46 . That is, even when the pressing load of the detent mechanisms  100  and  200  is increased, the coil spring  46  for the waiting mechanism is not compressed before the movement of the shift shaft  50 . 
     (3) The first detent mechanism  100  and the second detent mechanism  200  are arranged separately in both end portions in the axial direction of the shift shaft  50 . Thus, the holding force for the shift shaft  50  by the detent mechanisms  100  and  200  can be made uniform in the axial direction and hence a smooth operation of the shift shaft  50  is ensured. 
     (4) The shift position of the shift sleeve  90  is set up in the order of the neutral position, the high-speed forward movement position, and the low-speed forward movement position. Thus, during the traveling, when the shift is to be performed from the neutral position to the high-speed forward movement position, in case that the phase of the dog claws  84  of the counter high gear  73  for high speed that performs high-speed rotation does not coincide with the phase of the dog claws  85  of the shift sleeve  90 , the shift sleeve  90  is pushed back by a large reaction force from the counter high gear  73 . However, the reaction force is alleviated by the coil spring  46  for the waiting mechanism. 
     (5) Both ends of the coil spring  46  are accommodated respectively in the recess  45   a  of the coil spring holder  45  and in the recess  51   a  of the shift fork  51 . Thus, at the time of the shift operation, a bending does not occur in the coil spring  46  and hence the shift operation becomes smooth. Further, compact dimensions are achievable in the axial direction of the waiting mechanism  40 . 
     (6) As shown in  FIG. 8 , since the drive pin  44  is provided in the inner arm  43  and the long hole  47  is formed in the spring holder  45 , at the time of the shift operation, no rotation force is imparted to the shift shaft  50  by the inner arm  43 . Thus, the movement in the axial direction of the shift shaft  50  becomes smooth. 
     (7) In the configuration that the shift shaft  50  moves in the axial direction, the spring holder  45  plays the role of holding the coil spring  46  and the role of transmitting the operation force of the shift shaft  50  through the inner lever  43 . This reduces the number of components. 
     Other Embodiments 
     (1)  FIG. 10  shows a modification of the spring holder  45 . The spring holder  45  has a long hole  147  formed in a lower end surface and the inner lever  43  is provided with a drive pin  144  located in a front end portion. That is, in comparison with the above-mentioned configuration of  FIG. 9 , the members to which the long hole  147  and the drive pin  144  are attached are interchanged. 
     (2) The arrangement position of the elastic member for waiting mechanism (the coil spring) is not limited to the forward position of the shift shaft and may be, for example, a backward position, a lower position, or an upper position of the shift shaft as long as it is an outer position in the radial direction of the shift shaft. 
     (3) As for the operation force transmission mechanism, in addition to the above-mentioned push-pull cable type, the present technique is applicable also to a speed change apparatus employing an operation force transmission mechanism of rod type. 
     (4) The elastic member is not limited to the coil spring and may be a construction obtained by arranging a plurality of disc springs. Alternatively, a rubber sheet or a flat spring may be employed. 
     (5) In place of the recess  45   a , a cylindrical protrusion may be formed in the coil spring holder  45 . Further, in place of the recess  51   a , a cylindrical protrusion may be formed in the shift fork  51 . Then, both end parts of the coil spring  46  may be fit onto outer peripheral surfaces of both protrusions. 
     (6) The present invention is applicable also to a shift device whose shift positions consist of three or more gear modes of forward movement. 
     (7) The above-mentioned embodiment has been applied to a transmission mounted on a utility vehicle. However, the present invention may be applied also to a transmission mounted on a four-wheel vehicle of any other type or a motorcycle. 
     (8) The present invention is not limited to the configuration of the embodiment and includes various kinds of modifications as long as not departing from the contents described in the claims.