Patent Document

CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The present application claims priority under 35 USC 119(e) to Japanese Patent Application No. 2005-032125 filed on Feb. 8, 2005, the entire contents of which are hereby incorporated by reference.  
         [0002]     1. Field of the Invention  
         [0003]     The present invention relates to a clutch mechanism of a hydrostatic continuously variable transmission. More particularly, the present invention relates to a method for manufacturing a roller bearing member for receiving a pressing force of a roller for a centrifugal type governor clutch of a hydrostatic continuously variable transmission.  
         [0004]     2. Description of Background Art  
         [0005]     A roller bearing member for a centrifugal governor clutch according to the background art includes a pressure plate for receiving a pressing force of a roller and a shaft for guiding a motion of the pressure plate. In the background art, the centrifugal governor clutch for a hydrostatic continuously variable transmission includes a roller bearing member that has been manufactured such that the pressure plate and the shaft are integrally set. The pressure plate has a plate-like shape and the shaft has a cylindrical shape. Although the machining method should be originally different, the pressure plate and the shaft are integral members. Therefore, the entire member was necessarily manufactured through a cutting operation (refer to JP-A 070331/2004 (FIG. 1), for example). In addition, since the pressure plate is a plate-like member, the machining operation using cutting is difficult.  
       SUMMARY OF THE INVENTION  
       [0006]     An embodiment of the present invention is directed to the structure of a roller bearing member that can be manufactured by a simple machining operation that is suitable for its shape. Therefore, the efficiency of manufacture can be improved to reduce cost.  
         [0007]     An embodiment of the present invention can overcome the above-mentioned problems of the background art. Specifically, an embodiment of the present invention is directed to a clutch mechanism for a hydrostatic continuously variable transmission in which a hydraulic circuit comprised of a high pressure oil path for feeding working oil from a hydraulic pump to a hydraulic motor and a low pressure oil path for feeding working oil from said hydraulic motor to said hydraulic pump is constituted between said hydraulic pump and said hydraulic motor, said high pressure oil path and said low pressure oil path are shortened by sliding a clutch valve arranged at a shaft of the transmission through a centrifugal governor to change over a transmittance of power characterized in that the same is comprised of a cam plate member arranged at the end part of said transmission shaft; a roller engaged with said cam plate member and moved outwardly in a diametrical direction by a centrifugal force; a roller bearing member receiving a roller pressing force through outward motion of said roller and slid axially; a spring member for biasing said roller bearing member toward said roller; and said roller bearing member being formed such that a pressure plate and a shaft engaged with said clutch valve and slid are separately formed and integrally formed.  
         [0008]     In this embodiment of the present invention, the pressure plate and the shaft are separately formed and the pressure plate can be manufactured efficiently through press forming using a die. In addition, the shaft is not provided with a plate member before it is machined. Therefore, the cutting work performed by a machine can be efficiently carried out. Since both members are welded and integrally formed after their manufacturing, production efficiency is improved.  
         [0009]     Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention, and wherein:  
         [0011]      FIG. 1  is a side view of the motorcycle  1  including the power unit  2  of an embodiment of the present invention;  
         [0012]      FIG. 2  is a left side view of the power unit  2  mounted in the motorcycle;  
         [0013]      FIG. 3  is a cross-sectional cutaway view along lines III-III of  FIG. 2 ;  
         [0014]      FIG. 4  is a cross-sectional view along IV-IV of  FIG. 2 ;  
         [0015]      FIG. 5  is a vertical cross-sectional view of the static hydraulic continuously variable transmission T;  
         [0016]      FIG. 6  is a cross sectional view of an essential section of the static hydraulic continuously variable transmission T showing the vicinity of the distributor valve  160 ;  
         [0017]     FIGS.  7 ( a ) and  7 ( b ) are views of the cotter pin  151 , wherein  FIG. 7 ( a ) is a front view and  FIG. 7 ( b ) is a cross-sectional view along line  7 ( b )- 7 ( b ) of  FIG. 7 ( a );  
         [0018]     FIGS.  8 ( a ) and  8 ( b ) are views of the retainer ring  152 , wherein  FIG. 8 ( a ) is a front view and  FIG. 8 ( b ) is a cross-sectional view along line  8 ( b )- 8 ( b ) of  FIG. 8 ( a );  
         [0019]     FIGS.  9 ( a ) and  9 ( b ) are views of the C clip  153 , wherein  FIG. 9 ( a ) is a front view and  FIG. 9 ( b ) is a cross-sectional view along line  9 ( b )- 9 ( b ) of  FIG. 9 ( a );  
         [0020]      FIG. 10  is a vertical cross-sectional view of an essential section of the static hydraulic continuously variable transmission T showing the vicinity of the centrifugal governor clutch C; and  
         [0021]      FIG. 11  is a vertical cross-sectional view of an essential section of the static hydraulic continuously variable transmission T showing the supply passages for the operating fluid and the lubricant fluid. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0022]     The present invention will now be described in detail with reference to the accompanying drawings.  FIG. 1  is a side view of the motorcycle  1  containing the power unit  2  of an embodiment of the present invention. The motorcycle  1  includes a pair of main frames  4  that connect to a head pipe  3  and slope downwards to the rear. A pair of sub frames  5  slope downwards from the lower section of the head pipe  3  and bend rearwards. Respective rear tips of the sub frames connect to the rear end of the main frame  4 .  
         [0023]     A power unit  2  that includes an internal combustion engine  6  and a transmission  7  is mounted in a generally triangular space formed by the main frame  4  and the sub frame  5  as seen from the side. A front fork  8  is supported to allow rotation in the head pipe  3 . The steering handle  9  is mounted on the top end of the front fork  8 . A front wheel  10  is axially supported by a bottom end of the front fork  8 . A pair of rear forks  11  are supported on their forward end by the rear section of the main frame  4  and are capable of swinging upward and downward. A rear suspension (not shown in drawing) is mounted between the rear end of the main frame  4  and the center section of the rear fork  11 . A rear wheel  12  is axially supported on the rear end of the rear forks  11 .  
         [0024]     The internal combustion engine  6  is a water-cooled V-type two-cylinder combustion engine with the cylinders opening in a V-shape towards the front and rear. The crankshaft of the internal combustion engine  6  is perpendicular to the forward direction of the vehicle, and is installed facing towards the left and right of the vehicle. The transmission shaft of the transmission  7  is parallel to the crankshaft. The rear wheel drive shaft (not shown in the drawings) is connected to the connecting shaft  85  ( FIG. 2 ) perpendicular to the output shaft of the transmission, and extends rearward of the vehicle, reaching and driving the rotating shaft of the rear wheel  12 .  
         [0025]     An exhaust pipe  13  is connected to the exhaust port and is installed facing the front and rear of the two vehicle cylinders. The exhaust pipe  13  extends forwards of the internal combustion engine  6 , and extends under the transmission  7  to the frame rear section. The exhaust pipe  13  connects to the exhaust muffler  14 . A fuel tank  17  is mounted on the upper section of the (main) frame  4 , and a seat  18  is mounted to the rear. The internal combustion engine  6  is a water-cooled type. Cooling water having a temperature that rises during the process of cooling the cylinder and oil is cooled in the radiator  19  installed on the front end of the sub frame  5 .  
         [0026]      FIG. 2  is a left-side view of the power unit  2  mounted on the motorcycle. The arrow F indicates the front during installation in the frame. The front side cylinder  24 F and the rear side cylinder  24 R possess the same internal structure so the cross-section of only the rear side cylinder  24 R is shown. The crankcase rear section shows the state with the left crankcase cover removed and shows the positions of the main internal rotating shafts and gears and sprockets.  
         [0027]      FIG. 3  is a cross sectional view taken along lines III-III of  FIG. 2 . This figure is a cross sectional view including the rear side cylinder  24 R and the crank shaft  30  and the transmission shaft  100  of the static hydraulic continuously variable transmission T. The rear side cylinder  24 R is a cylinder holding the piston  33  connecting to the left side crankpin  31 .  
         [0028]     The main components of the power unit  20  in  FIG. 2  and  FIG. 3  are the crankcase  20  comprised of a left crankcase  20 L and a right crankcase  20 R, a left crankcase cover  21 L, a right crankcase cover  21 R, and a cylinder block  25 , a cylinder head  26  and a cylinder head cover  27  respectively installed with the front side cylinder  24 F and the rear side cylinder  24 R. The following description of the cylinder sections is based on the rear cylinder  24 R.  
         [0029]     In  FIG. 3 , the crankshaft  30  is supported to allow free rotation by the left side bearing  28  and the right side bearing  29  held in the left/right crankcases  20 L and  20 R. A connecting rod  32  and a piston  33  are connected to the left side crankpin  31  on the crankshaft  30 . The piston  33  is held to allow sliding movement in the cylinder hole  34  of the cylinder block  25 . A combustion chamber  35  is formed in the section facing the piston  33  of the cylinder head  26 . A spark plug  36  is inserted through the wall of the cylinder head  26 . A tip of the spark plug enters the combustion chamber  35  and a rear end of the spark plug is exposed externally.  
         [0030]     In  FIG. 2 , an exhaust port  40  and an intake port  41  are connected to the combustion chamber  35 . The exhaust port  40  extends forwards in the front side cylinder  24 , and rearward in the rear side cylinder  24 R. The intake port  41  extends upwards for either cylinder in the space between both cylinders. The exhaust port  40  contains an exhaust valve  42 , and the intake port  41  contains an intake valve  43 . A camshaft  44  is installed inside the cylinder head cover  27 . An exhaust rocker arm shaft  45 , and an intake rocker arm shaft  46  are installed above the camshaft  44 . The exhaust rocker arm  47  and the intake rocker arm  46  installed on these arm shafts are driven by the cam  44   a ,  44   b  of the camshaft  44 . The exhaust rocker arm  47  and the intake rocker arm  46  press the stems of the intake valve  43  and the exhaust valve  42  to drive each valve to open or close. In  FIG. 3 , the camshaft  44  is driven by a camshaft drive chain  51  hooked on the camshaft drive sprocket  50  installed in the crankshaft  30  and the camshaft auxiliary sprocket  49  installed on the end of the camshaft  44 .  
         [0031]     In  FIG. 2 , a low-pressure oil pump and a high-pressure oil pump are integrated via an oil pump shaft  91  into an oil pump cluster  90 , at a lower section of the crankcase  20 . The low-pressure oil pump feeds oil towards the internal combustion engine  6 , and the high-pressure oil pump feeds oil towards the static hydraulic continuously variable transmission T. The oil pump cluster  90  suctions oil within the oil pan  92  by way of the lower section oil strainer  93 . The internal combustion engine  6  drives the oil pump cluster  90  via an oil pump drive chain  96  engaged on the oil pump shaft drive sprocket  95  installed in the crankshaft  30 , and the oil pump auxiliary drive sprocket  94  inserted into the oil pump shaft  91 . An oil cooler  97  and a low-pressure oil filter  98  can be seen on the rear section of the crankcase  20 . The high-pressure oil filter is installed on the right side of the crankcase and is therefore not shown in the drawing.  
         [0032]     In  FIG. 3 , the crankshaft output gear  37  that is installed on the left end of the crankshaft  30  functions as a gear in combination with the cam type torque damper  38 . The crankshaft output gear  37  engages with the transmission input gear  116  installed on the casing  110  of the tilt plate plunger-type hydraulic pump P of the static hydraulic continuously variable transmission T. The crankshaft output gear  37  and the cam type torque damper  38  are installed on a collar  60  that is spline-coupled to the crankshaft  30 . The crankshaft output gear  37  is mounted for free rotation on the collar  60 . A recessed cam  37   a  with a concave surface in an arc-shape is formed on a side surface of the crankshaft output gear  37 . A lifter  61  is inserted on the outer circumferential spline of the collar  60  to allow axial movement. A protruding cam  61   a  with an arc-shaped protruding surface is formed on the edge of the lifter  61 . The protruding cam  61   a  engages with the recessed cam  37   a . A spring holder  62  is fastened to the edge of the collar  60  with a spline and cotter pin. A flat spring  63  is installed between the spring holder  62  and the lifter  61 . The flat spring  63  forces the protruding cam  61   a  towards the recessed cam  37   a.    
         [0033]     During operation at a fixed speed, the torque of the crank shaft  30  is transferred in sequence to the collar  60 , the lifter  61 , the protruding cam  61   a , the recessed cam  37   a , and the crankshaft output gear  37 . The crankshaft output gear  37  rotates along with the crankshaft  30 . When excessive torque is applied to the crankshaft  30 , the protruding cam  61   a  slides along the circumference of the cam surface of the recessed cam  37   a , and moves axially opposing the force of the flat spring  63 , absorbing the huge torque and alleviating the impact.  
         [0034]     The crankshaft output gear  37  is a gear for reducing backlash. The crankshaft output gear  37  is comprised of a thick, main gear  64  in the center, and a thin auxiliary gear  65  supported to allow concentric rotation versus the main gear  64 , and an auxiliary gear coil spring  66  for applying a peripheral force via the auxiliary gear  65  on the main gear  64 . The auxiliary gear applies a circumferential (peripheral) force to eliminate the backlash gap that occurs between the main gear and the normal gear, when the backlash reducing gear engages with a normal gear and so can eliminate looseness (play) and alleviate noise to quiet the mechanism. In the present case, the noise from the crankshaft output gear  37  engaging with the transmission input gear  116  is reduced.  
         [0035]     In  FIG. 3 , the static hydraulic continuously variable transmission T is installed rearward of the crankshaft  30 . The static hydraulic continuously variable transmission T is a device combining a centrifugal governor clutch C, a tilt plate plunger-type hydraulic pump P, and tilt plate hydraulic motor M via the motor transmission shaft  100 . When the rotation speed of the casing  110  of the tilt plate plunger-type hydraulic pump P exceeds a specified speed, the transmission input gear  116  connects (engages) the static hydraulic continuously variable transmission T due to the centrifugal force effect of the governor clutch C to change the speed. The static hydraulic continuously variable transmission T changes the speed by changing the speed (gear) ratio according to the tilted state of the tilt plate for the tilt plate hydraulic motor M. The rotational force for the change in speed is extracted from the motor transmission shaft  100  that rotates as one piece with the hydraulic pump P and the hydraulic motor M. A motor servomechanism changes the tilt angle of the tilt plate of the tilt plate hydraulic motor M. The structure and effect of the static hydraulic continuously variable transmission T will be described below.  
         [0036]      FIG. 4  is a cross-sectional view taken along lines IV-IV in  FIG. 2 . This is the path for transmitting power from the transmission shaft  100  to the connecting shaft  85 . A neutral-drive selector shaft  76  for the neutral-drive selector clutch  75  for selecting the neutral and drive states, and in parallel with the transmission shaft  100 , is supported via ball bearings in the right crankcase  20 R and the left crankcase  20 L to allow rotation. An output shaft  80  in parallel with the neutral-drive selector shaft  76  is supported via ball bearings in the right crankcase  20 R and the right crankcase cover  21 R to allow rotation. Furthermore, the connecting shaft  85  perpendicular to the output shaft  80  is supported by the connecting shaft support section  84  installed near the left edge of the output shaft  80  to allow rotation. The connecting shaft support section  84  is installed on the outer side of the left crankcase  20 L (Also see  FIG. 2 .).  
         [0037]     In  FIG. 4 , a gear  68  is clamped to the transmission shaft  100 . A gear  77  is inserted into the neutral-drive selector shaft  76  to allow rotation versus the shaft. The gear  77  engages with the transmission output gear  68  affixed to the transmission  100 . The swing member  78  including a mesh gear  78   a  and adjacently connected to the gear  77  is inserted to allow sliding axially to the neutral-drive selector shaft  76 . The neutral-drive selector clutch  75  includes the neutral-drive selector shaft  76 , the gear  77 , and a swing member  78 ; and cuts off or connects the drive power conveyed from the transmission drive shaft  100  to the output shaft  80 . When the mesh gear  78   a  of swing member  78  releases from the gear  77 , the neutral-drive selector clutch  75  sets a neutral state, and slides the swing member  78 . When the mesh gear  78   a  engages with the mesh section of the gear  77 , the drive power transmission path is connected, and the drive state is set.  
         [0038]     In  FIG. 4 , a gear  79  is inserted on the neutral-drive selector shaft  76  and adjacently contacts the gear  77  on the opposite side of the slide member  78 . A gear  81  is inserted on the right end of the output shaft  80  to engage with the gear  79  on the neutral-drive selector shaft  76 . A bevel gear  82  is formed as one piece with the other end of the output shaft  80 . A bevel gear  86  is formed as one piece on the front end of the connecting shaft  85 , and engages with the bevel gear  82  of the output shaft  80 . A spline  85   a  is mounted on the rear end of the connecting shaft  85  for connection to the rear wheel drive shaft. The rotational output power of the static hydraulic continuously variable transmission T is transmitted to the rear wheel transmission shaft by way of these shafts and gears.  
         [0039]      FIG. 5  is a vertical cross-sectional view of the static hydraulic continuously variable transmission T. The static hydraulic continuously variable transmission T is made up of a tilt plate plunger-type hydraulic pump P, a tilt plate plunger-type hydraulic motor M, and a centrifugal governor clutch C. The transmission shaft  100  functioning as the output shaft for the static hydraulic continuously variable transmission T is mounted to pass through the center (of transmission T). The left end of the transmission shaft  100  is supported to allow rotation by the ball bearings B 1 , B 2  on the left crankcase cover  21 L, and the right end is supported to allow rotation by the ball bearing B 3  on the right crankcase  20 R.  
         [0040]     The hydraulic pump P includes a pump casing  110  capable of rotating relative to the transmission shaft  100  and installed concentrically with it; a pump tilt plate  111  installed tilted at a specific angle versus the rotating shaft of the pump casing in the interior of the pump casing  110 , and a pump cylinder  112  installed facing this same pump tilt plate  111 ; and multiple pump plungers  114  installed to slide within the pump plunger holes  113  arrayed in a ring shape enclosing the shaft center within the pump cylinder  112 . One end of the pump casing  110  is supported to allow rotation by the bearing B 2  in the transmission shaft  100 , and the other end is supported to allow rotation by the bearing B 4  in the pump cylinder  112 , and also supported to allow rotation by the bearing B 1  in the left crankcase cover  21 L. The pump tilt plate  111  is installed tilted at a specified angle to allow rotation relative to the pump casing  110  by the bearings B 5 , B 6 .  
         [0041]     The transmission input gear  116  affixed by the bolt  115  is installed on the outer circumference of the pump casing  110 . The outer end of the pump plunger  114  engages with the tilt plate surface  111   a  of the pump tilt plate  111  protruding outwards. The inner edge of the pump plunger  114  forms a pump fluid chamber  113   a  in the pump plunger hole  113 . A pump passage opening  117  functioning as a dispensing hole and an intake hole is formed on the edge of the pump plunger hole  113 . The pump casing  110  rotates when the transmission input gear  116  is made to rotate. The pump tilt plate  111  installed inside slides along with the rotation of the pump casing  110 . The pump plunger  114  moves back and forth within the pump plunger hole  113  according to the swing of the tilt plate surface  111   a . The hydraulic fluid within the pump fluid chamber  113   a  is dispensed and suctioned.  
         [0042]     The pump eccentric ring member  118  is installed by a bolt  119  on the right edge of the pump casing  110  in the center of the drawing. The inner circumferential surface  118   a  of the pump eccentric ring member  118  is formed in a tubular shape that is off-center versus the rotating shaft of the pump casing  110 . Therefore, this inner circumferential surface  118   a  is also a tubular shaped offset in the same way versus the center line of the transmission shaft  100  and the pump cylinder  112 .  
         [0043]     The casing  130  of the hydraulic motor M is affixed and supported while clamped to the right crankcase  20 R. The motor casing  130  is formed from the spherical member  131  and the elongated member  132 , and is clamped by the bolt  133 . A support spherical surface  131   a  is formed on the inner surface of the spherical member  131 . The hydraulic motor M is comprised of a motor casing  130 , and a motor swing member  134  that is slide connected and supported on the support spherical surface  131   a . A motor tilt plate  135  is supported to allow rotation by the bearings B 7 , B 8  within the motor swing member  134 . A motor cylinder  136  faces the motor tilt plate  135 . A motor plunger  138  is installed to allow sliding within the multiple plunger holes  137  passing through in the axial direction and arrayed in a ring shape enclosing the center axis of the motor cylinder  136 . The motor cylinder is supported for rotation along the external circumference in the elongated member  132  of the motor casing  130  by way of the bearing B 9 . The motor swing member  134  is capable of swinging in a movement centering on the center O extending at a right angle (direction perpendicular to the paper surface) to the center line of the transmission shaft  100 .  
         [0044]     The outer side edge of the motor plunger  138  engages with the tilt plate surface  135   a  of the motor tilt plate  135  protruding outwards. The inner side edge of the motor plunger  138  forms a motor fluid chamber  137   a  within the motor plunger hole  137 . A motor passage opening  139  functioning as an intake port and a dispensing (exhaust) port for the motor is formed in the edge of the motor plunger hole  137 . The edge of the motor swing member  134  is formed as an arm  134   a  protruding to the outer side and protrudes outwards towards the radius to connect to the motor servo mechanism S. The arm  134   a  is controlled by the motor servo mechanism S to move left and right, and is controlled to swing centering on the swing center O of the motor swing member  134 . When the motor swing member  134  swings, the motor tilt plate  135  supported internally inside it ( 134 ) also swings, and changes the angle of the tilt plate.  
         [0045]      FIG. 6  is an enlarged cross-sectional view of the vicinity of the distributor valve  160  of the static hydraulic continuously variable transmission T. The distributor valve  160  is installed between the pump cylinder  112  and the motor cylinder  136 . The valve body  161  of the distributor valve  160  is supported between the pump cylinder  112  and the motor cylinder  136 , and is integrated with these cylinders by brazing. The motor cylinder  136  is coupled to the transmission shaft  100  by a spline  101 . The pump cylinder  112 , the distributor valve  160 , and the motor cylinder  136  rotate with the transmission shaft  100  as one unit. This integrated pump cylinder  112 , valve body  161  of the distributor valve  160 , and the motor cylinder  136  are called the output rotation piece R. The structure for attaching the output rotation piece R to the transmission shaft will now be described. A large diameter section  102  that is short along the axial length is formed on the outer circumferential side of the transmission shaft  100  corresponding to the left edge position of the pump cylinder. The left edge surface of the pump cylinder  112  contacts the edge surface of this large diameter section  102 , to perform positioning to the left.  
         [0046]     The right side positioning of the output rotation piece R, is performed by the stop member  150  installed on the transmission shaft  100  facing the motor cylinder  136 . The stop member  150  includes a cotter pin  151 , a retainer ring  152 , and a C ring  153 . To install the stop member  150 , a ring-shaped first stop groove  103 , and second stop groove  104  are formed across the outer circumference of the spline  101 . A pair of cotter pins  151  is separately formed in a semicircular shape shown in  FIG. 7  and is installed in the first stop groove  103 . A retainer ring  152  is installed above it as shown in  FIG. 8 . The tip section  152   a  of the retainer ring  152  covers the outer circumferential surface of the cotter pin  151 , and the inward facing flange  152   b  of retainer ring  152  contacts the side surface of the cotter pin. Moreover, the C ring  153  is installed as shown in  FIG. 9  in the second stop groove  104 , and prevents the retainer ring  152  from coming loose. As a result of the above, the right edge surface of the motor cylinder  136  directly contacts the stop piece  150  and is positioned towards the right.  
         [0047]     The output rotation piece R is in this way positioned to the left by the large diameter piece  102  via the spline  101 ; and positioned to the right versus the transmission shaft  100  by the stop piece  150  and rotates along with the transmission shaft  100  as one piece. A lubricating oil injection nozzle  152   e  connecting the outer tilt plate  152   d  and the inner circumferential ring groove  152   c  of the retainer ring  152  is drilled as three sections along the entire circumference.  
         [0048]     In  FIG. 6 , the multiple pump side valve holes  162  and motor side valve holes  163  extending towards the diameter and positioned at equal spaces along the periphery within the valve body  161  forming the distributor valve  160 , are formed in an array of two rows. A pump side switcher valve  164  is installed within the pump side valve hole  162 , and a motor side switcher valve  165  is installed within the motor side valve hole  163  and each ( 164 ,  165 ) is capable of sliding movement.  
         [0049]     The multiple pump side valve holes  162  are formed to correspond to the pump plunger holes  113 . Each of the pump side valve holes  162 , and pump flow passages  117  formed in the inner side edge of the pump plunger holes  113 , and the multiple pump side connecting passages  166  formed to respectively connect to them ( 162 ,  117 ), are formed in the valve body  161 . The motor side valve holes  163  are formed to correspond to the motor plunger holes  137 . The motor connecting passages  139  formed on the inner edge side of the motor plunger holes  137 . The motor connecting passages  167  connecting with the respective motor side valve holes  163  are formed in the valve body  161 .  
         [0050]     A pump side cam ring  168  is installed at a position enclosing the outer circumferential edge of the pump side switcher valve  164  on the distributor valve  160 . A motor side cam ring  169  is installed at a position enclosing the outer circumferential edge of the motor side switcher valve  165  on the distributor valve  160 . The pump side cam ring  168  is installed onto the inner circumferential surface  118   a  of pump eccentric ring member  118  clamped by a bolt  119  to the tip of the pump casing  110  ( FIG. 5 ). The motor cam ring  169  is installed onto the inner circumferential surface  140   a  of the motor eccentric ring member  140  positioned in contact with the tip of the elongated member  132  of motor casing  130  ( FIG. 5 ). The outer side edge of the pump side switcher valve  164  on the inner circumferential surface of the pump side cam ring  168  is engaged to allow sliding movement via the pump side restrictor ring  170 . The outer side edge of the motor side switcher valve  165  on the inner circumferential surface of the motor side cam ring  169  is engaged to allow sliding movement via the motor side restrictor ring  171 . The cam ring and the restrictor ring are both capable of relative rotation on either the pump side or the motor side.  
         [0051]     A ring-shaped recess functioning as the inner side passage  172  is carved onto the outer circumferential surface of the transmission shaft  100  facing the inner circumferential surface of the valve body  161 . The inner edge of the motor side valve hole  163  and the pump side valve hole  162  are connected to this inner side passage  172 . An outer side passage  173  is formed near the external circumference of the valve body  161  to connect with the pump side valve hole  162  and motor side valve hole  163 .  
         [0052]     The operation of the distributor valve  160  will now be described. When the drive force of the internal combustion engine is conveyed to the transmission input gear  116  and the pump casing  110  rotates, the pump tilt plate  111  swings according to that rotation. The pump plunger  114  engaging with the tilt plate surface  111   a  of the pump tilt plate  111  moves axially back and forth within the pump plunger hole  113  by way of the swinging of the pump tilt plate  111 . Hydraulic fluid is dispensed via the pump passage opening  117  from the pump fluid chamber  113   a  during inward movement of the pump plunger  113 , and hydraulic fluid is suctioned into the pump fluid chamber  113   a  via the pump passage opening  117  during outward movement.  
         [0053]     At this time, the pump side cam ring  168  installed on the inner circumferential surface  118  of the pump eccentric ring member  118  coupled to the edge of the pump casing  110 , rotates along with the pump casing  110 . The pump side cam ring  168  is offset (eccentric) versus the rotation center of the pump casing  110 . In other words, it is installed offset (eccentric) to the valve body so that the pump side switcher valve  164  moves back and forth along the diameter within the pump side valve hole  112 , according to the rotations of the pump side cam ring  168 .  
         [0054]     The pump side switcher valve  164  moves back and forth in this way, and when moving inwards along the diameter within the valve body  161 , the pump side connecting passage  166  opens outwards along the diameter via a small diameter section  164   a  of the pump side switcher valve  164 , and connects the pump passage opening  117  and the outer side passage  173 . When the pump side switcher valve  164  moves outward along the diameter within the valve body  161 , the pump side connecting passage  166  opens inwards along the diameter, and connects the pump passage opening  117  and the inner side passage  172 .  
         [0055]     The pump tilt plate  111  swings along with the rotation of the pump casing  110 , the pump side cam ring  168  moves the pump side switcher valve  164  back and forth along the diameter, to match the position (lower dead point) where the pump plunger  114  is pressed farthest to the outside, and the position (upper dead point) where furthermost to the inside during its back and forth movement. The pump plunger  114  consequently moves from the lower dead point to the upper dead point along with the rotation of the pump casing  110 , and the hydraulic fluid within the pump fluid chamber  113   a  is dispensed from the pump passage opening  117 . The pump passage opening  117  at this time is connected to the outer side passage  173  so that the hydraulic fluid is sent to the outer side passage  173 . On the other hand, when the pump plunger  114  moves from the upper dead point to the lower dead point along with the rotation of the pump casing  110 , the hydraulic fluid within the inner side passage  172  is suctioned inside the pump fluid chamber  113   a  via the pump passage opening  117 . In other words, when the pump casing  110  is driven, hydraulic fluid is dispensed from a pump fluid chamber  113   a  on one side and supplied to the outer side passage  173 , and hydraulic fluid is suctioned from the inner side passage  172  into the pump fluid chamber  113   a  on the other side of the transmission shaft  100 .  
         [0056]     However, the motor side cam ring  169  installed on the inner circumferential surface  140   a  of the motor ring eccentric member  140  positioned in sliding contact on the edge of the motor casing  130 , is positioned eccentrically versus the rotation center of the transmission shaft  100  and the output rotation piece R, and motor cylinder  136 , when the motor ring eccentric member  140  is in the usual position, When the motor cylinder  136  rotates, the motor side switcher valve  165  moves back and forth along the diameter within the motor side valve hole  163  according to that ( 136 ) rotation.  
         [0057]     When the motor side switching valve  165  moves inwards along the diameter within the valve body  161 , the small diameter section  165   a  of the motor side switching valve  165  opens the motor side connection path  167  to the outside, connecting the motor passage opening  139  and the outer side passage  173 . When the motor side switching valve  165  moves outward along the diameter within the valve body  161 , the motor side connection path  167  opens inwards along the diameter, connecting the motor passage opening  139  and the inner side passage  172 .  
         [0058]     The hydraulic fluid dispensed from the hydraulic pump P is sent to the outer side passage  173 , and this hydraulic fluid is supplied via the motor side connection path  167 , and the motor passage opening  139  to inside the motor fluid chamber  137   a , and the motor plunger  138  is pressed axially outward. The outer edge of the motor plunger  138  is configured to slide-contact to the section where the motor tilt plate  135  moves from the upper dead point to the lower dead point. Due to this force pressing axially outwards, the motor plunger  138  moves along with the motor tilt plate  135 , along the tilted surface formed by the motor sliding member  134  and the bearing B 7 , B 8 . The motor cylinder  136  is consequently pressed by the plunger  138  and driven. Along with the rotation of the motor cylinder  136 , the motor side cam ring  169  makes the motor side switching valve  165  move back and forth along the diameter in the valve body  161 , corresponding to the back and forth movement of the motor plunger  138 .  
         [0059]     The motor cylinder  136  on the opposite side moves the periphery of the transmission shaft  100  along with the rotation of the motor tilt plate  135  centering on the transmission shaft  100 , moving from the lower dead point to the upper dead point. The hydraulic fluid within the motor fluid chamber  137   a  is sent from the motor passage opening  139  to the inner side passage  172 , and is suctioned via the pump side connecting passages  166  and pump passage opening  117 .  
         [0060]     A hydraulic shut off circuit joining the tilt plate hydraulic motor M and the tilt plate plunger-type hydraulic pump P is in this way formed by the distributor valve  160 . The hydraulic fluid dispensed according to the rotations of the hydraulic pump P is sent to the hydraulic motor M via the other hydraulic shut-off circuit (outer side passage  173 ), driving it. Moreover, the hydraulic fluid dispensed along with the rotation of the hydraulic motor M is returned to the hydraulic pump P via the other hydraulic shut-off circuit (inner side passage  172 ).  
         [0061]     In the static hydraulic continuously variable transmission T described above, the hydraulic pump P is driven by the internal combustion engine  6 , the rotation drive power of the hydraulic motor M is converted by the distributor valve  160  and the hydraulic motor M, extracted from the transmission shaft  100 , and transmitted to the vehicle wheels. When the vehicle is being driven, the outer side passage  173  is the high pressure side fluid path, and the inner side passage  172  is the low pressure side. On the other hand, during times such as driving downhill, the drive force for the vehicle wheels is transmitted from the transmission shaft  100  to the hydraulic motor M, and the rotational drive force of the hydraulic motor P renders the effect of an engine brake conveyed to the internal combustion engine  6 , the inner side passage  172  is the high pressure side fluid path, and the outer side passage  173  is the low pressure side fluid path.  
         [0062]     The gear ratio of the static hydraulic continuously variable transmission T can be continuously changed by varying the tilt angle of the motor swing member  134 . The tilt angle of the motor swing member  134  is changed for a motor tilt plate angle of zero or in other words, when the motor tilt plate is perpendicular to the transmission shaft, the top gear ratio is reached, the amount of offset (eccentricity) of the eccentric (ring) member  140  reaches zero due to the effect of the lockup actuator A ( FIG. 5 ), the center of the motor cylinder  136  matches the center of the eccentric member  140 , and the pump casing  110 , the pump cylinder  112 , the motor cylinder  136 , and the transmission shaft  100  rotates as one unit to efficiently transfer the drive power.  
         [0063]      FIG. 10  is a vertical cross-sectional view of the vicinity of the centrifugal governor clutch C. When the inner side passage  172  and the outer side passage  173  are connected in the static hydraulic continuously variable transmission T, the high hydraulic pressure is no longer applied, and drive power is no longer transmitted between the hydraulic pump P and the hydraulic motor M. In other words, clutch control is implemented by controlling the degree of opening of the connection between the inner side passage  172  and the outer side passage  173 .  
         [0064]     The centrifugal governor clutch C includes a spring sheet member  182  and a cam plate member  181  clamped by a bolt  180  to the edge of the pump casing  110 . A roller  183  is held respectively within the multiple cam plate grooves  181   a  formed extending diagonally along the diameter on the inner surface of the cam plate member  181 . A pressure plate  184  includes an arm section  184   a  facing the cam plate groove  181   a . A coil spring  185  has one end supported by the spring sheet member  182  and the other end acting on the pressure plate  184  for making the arm section  184   a  of the pressure plate  184  apply a pressing force on the inside of the groove  181   a . A slide shaft  186  slides along the axial line of the transmission shaft and is inserted into the center hole  181   b  of the cam plate member  181  and also passes through the center section of the pressure plate  184 . A rod-shaped clutch valve  187  is engaged with the clutch valve engage section  186   a  of the slide shaft  186 . One end of the coil spring  185  is supported by the spring sheet  182   a  formed on the inner-facing flange of the spring sheet member  182 . The pressure plate  184  and the slide shaft  186  are both fabricated as separate pieces, and then coupled into a single piece to comprise the roller bearing member  188 . The pressure plate  184  is fabricated by forming it in a press, and the slide shaft  186  fabricated by cutting with machining tools and both parts are then welded together into one piece.  
         [0065]     When the pump casing  110  is in a static state, or in other words a state where neither the cam plate member  181  or the spring sheet member  182  are rotating, the arm section  184   a  presses the roller  183  into the cam plate groove  181   a  by the pressing force applied to the pressure plate  184  by the coil spring  185 . The cam plate groove  181   a  is in a tilted state so that the roller  183  is pressed along the diameter of the cam plate member  181 , and the pressure plate  184 , and the swing axis  186  integrated with it, and the rod clutch valve  187  engaged in the swing shaft  186  are in a state shifted to the left.  
         [0066]     When the pump casing  110  is driven by the rotation of the transmission input gear  116  ( FIG. 5 ), and the cam plate  181  and the spring sheet member  182  rotate, the roller  183  is pressed back along the tilted surface of the cam plate member  181  outwards along the diameter by centrifugal force, and presses the arm section  184   a  to the right and the pressure plate  184  moves to the right while opposing the force of the coil spring  185 . The amount of movement towards the right of the pressure plate  184  and the slide shaft  186  functioning as one piece with it are determined by the centrifugal force acting on the roller  183 . In other words, it (amount of movement) is determined according to the rotational speed of the pump casing  110 . When the rotational speed of the pump casing  110  increases, the rod clutch valve  187  engaged in the slide shaft  186 , extends along the inner section of the transmission shaft  100 , and shifts to the inner part of the clutch valve hole  105 . The centrifugal governor mechanism is in this way configured to apply a centrifugal force to the roller  183  by utilizing the centrifugal force from the rotation of the pump casing.  
         [0067]     An inner side connecting fluid path  190  is formed in the transmission shaft  100  as shown in  FIG. 10  that joins the clutch valve hole  105  and the inner side passage  172 . An outer side connecting fluid path  191  joining the clutch valve hole  105  and an outer side passage  173 , and a ring-shaped groove  192  and a tilt fluid path  193  for a short connection are formed in the transmission shaft  100  and the pump cylinder  112 . When the pump casing  110  is in a static state, the inner side connecting fluid path  190  and the outer side connecting fluid path  191  are connected by way of the small diameter section  187   a  of the rod-shaped clutch valve  187 , and consequently the inner side passage  172  and outer side passage  173  are connected so the clutch is disengaged.  
         [0068]     When the pump casing rotation exceeds the specified speed, and the rod-shaped clutch valve  187  shifts to the innermost section of the clutch valve hole  105  due to effect of centrifugal force from the governor mechanism, the small diameter section  187   a  of the rod-shaped clutch valve  187  releases (away) from the opening on the clutch valve hole  105  side of the outer side connecting fluid path  191 , and the outer side connecting fluid path  191  opening is blocked by the large diameter side surface  187   b  of rod-shaped clutch valve  187  (See position of rod-shaped clutch valve  187  in  FIG. 6 .). The connection between the inner side passage  172  and outer side passage  173  is therefore blocked and an oil circulation shut-off circuit is formed from the hydraulic pump P and outer side passage  173  and hydraulic motor M and inner side passage  172 , and the static hydraulic continuously variable transmission T functions. Switching from a clutch released state to a clutch engaged state is performed by the roller so that the clutch gradually becomes engaged (connected) according to this movement.  
         [0069]      FIG. 11  is a vertical cross sectional view of an essential section of the static hydraulic continuously variable transmission T showing the supply path for the lubricant fluid and the operating (hydraulic) fluid. The operating (hydraulic) fluid is supplied from the high-pressure oil pump of the oil pump cluster  90  driven by the internal combustion engine, via the fluid path within the crankcase, from the right end, to the transmission shaft center fluid path  200  formed along the axis and in the center of the transmission shaft  100 . The innermost section of the transmission shaft center fluid path  200  is joined to the fluid path  201  extending along the diameter to the outer circumference. The fluid path  201  is also joined with the output rotation piece inner fluid path  202  formed in parallel with the transmission shaft  100  within the output rotation piece R (motor cylinder  136 , valve body  161 , pump cylinder  112 ) that rotates as one piece with the transmission shaft  100 . The output rotation piece inner fluid path  202  is a fluid path including the fluid path  202   a  within the motor cylinder  136 , the fluid path  202   b  within the valve body  161 , and the fluid path  202   c  within the pump cylinder  112 .  
         [0070]     A check valve  210  for supplying replacement fluid within the outer side passage  173  is installed within the pump cylinder  112 . The output rotation piece inner fluid path  202  is joined to the check valve  210  via the fluid path  203  facing outwards along the diameter in the innermost section ( 202 ), and if necessary (according to leakage of operating fluid from the hydraulic shut-off circuit), operating fluid is supplied to the outer side passage  173  of the valve body  161 . A check valve and fluid path for supplying operation fluid to the inner side passage  172  are installed in the same way in another section of the pump cylinder  112 , and if necessary also supply operating fluid to the inner side passage  172  (omitted from drawing).  
         [0071]     An outer ring groove  204  is formed on the outer circumference of the transmission shaft  100  corresponding to the innermost section of the output rotation piece inner fluid path  202 , and connects to the innermost section of the output rotation piece inner fluid path  202 . An inner ring groove  205  is formed on the inner circumference of the clutch valve hole  105  of the transmission shaft  100 , and connects to the outer ring groove  204  at one location via the connecting fluid path  206 . An orifice  206   a  is formed in the connecting fluid path  206 . On the transmission shaft  100 , a lubricant oil injection nozzle  207  connecting to the inner ring groove  205  of the clutch valve hole and facing the external circumference of the transmission shaft  100  is drilled at three locations on the transmission shaft periphery. A portion of the oil supplied within the output rotation piece inner fluid path  202  is injected by way of the lubricant oil injection nozzle  207 , and the outer ring groove  204 , the connecting fluid path  206 , the inner ring groove  205 , and lubricates the pump tilt plate  111 , etc.  
         [0072]     A fluid path  208  is formed at one location from the transmission shaft center fluid path  200  along the diameter, facing towards the stop member  150  on the right edge positioner section of the output rotation piece R on the transmission shaft  100 , and an orifice  208   a  is formed on its inner edge section. The outer edge section of the fluid path  208  connects along the diameter to the ring groove  152   c  formed on the inner circumference of the retainer  152 . A portion of the oil supplied to inside the transmission shaft fluid path  200  is supplied via the fluid path  208  and the inner ring groove  152   c , to the lubricant oil injection nozzle  152   e  formed at three locations on the periphery of the inner ring groove  152   c  and the outer tilt plate  152   d  of the retainer ring  152 ; and is dispensed from the lubricant oil injection nozzle  152   e  and lubricates the motor tilt plate  135 , etc.  
         [0073]     The distance L 1  between the inner edge surface  113   b  of the pump plunger hole  113  and the pump side edge  161   a  of the valve body  161 , is made large compared to the distance L 2  between the inner edge surface  137   b  of the motor plunger hole  137  and the motor side surface  161   b  of the valve body  161 . The larger distance is required because it is necessary to form a tilt fluid path  193  ( FIG. 10 ) joining the clutch valve hole  105  and the outer side passage  173  between the inner edge surface  113   b  of the pump plunger hole  113  of pump cylinder  112  and pump side edge  161  a of the valve body  161  on the pump side; and therefore the pump plunger hole  113  are separated from the valve body  161 . There is no need to form a tilt fluid path on the (other) motor M side and therefore the distance between the inner edge surface  137   b  of the motor plunger hole  137  and the motor side surface  161   b  of the valve body  161  is small.  
         [0074]     In the clutch mechanism of the hydrostatic continuously variable transmission of the preferred embodiment described above in detail, the pressure plate  184  and the slide shaft  186  are separately formed, the pressure plate  184  is efficiently manufactured through a press forming using a die and the slide shaft  186  is not accompanied by the plate, so that the cutting work with a machine can be efficiently performed. After both portions are manufactured, they are welded and integrally formed to enable themselves to become the roller bearing member  188 , so that production efficiency is improved. Furthermore, the aforesaid integral formation can also be carried out by brazing and the like in addition to welding.  
         [0075]     The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims.

Technology Category: 2