Patent Publication Number: US-8973543-B2

Title: Valve timing controller and assembling method of the same

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on Japanese Patent Application No. 2012-14060 filed on Jan. 26, 2012, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a valve timing controller and an assembling method of the valve timing controller. 
     BACKGROUND 
     A valve timing controller controls opening and closing timing of an intake valve or an exhaust valve in an internal combustion engine by changing a rotation phase between a crankshaft and a camshaft. The valve timing controller has a housing rotating with the crankshaft, and a vane rotor rotating with the camshaft. The valve timing controller controls the valve timing by supplying working oil to an advance chamber or a retard chamber defined in the housing, so as to rotate the vane rotor. JP-2003-314229A (US 2003/0196627) describes a check valve system in which a reed valve is disposed in an oil passage which supplies the working oil to the advance chamber and the retard chamber as a check valve. 
     If a cross-sectional area of the oil passage connected to the reed valve is made smaller, the valve opening speed of the reed valve is made faster. However, in this case, a large pressure loss is generated when a large amount of the working oil is made to flow the oil passage, so the responsivity becomes worse because the relative rotation speed of the vane rotor cannot be raised. 
     In contrast, if the cross-sectional area of the oil passage is made larger, the valve opening speed of the reed valve becomes slow when a small amount of the working oil is made to flow the oil passage. In this case, the reed valve cannot work as the check valve and the responsivity becomes worse. 
     SUMMARY 
     It is an object of the present disclosure to provide a valve timing controller which accurately works even when a flow rate of working oil is varied. It is another object of the present disclosure to provide an assembling method of the valve timing controller. 
     According to an example of the present disclosure, a valve timing controller controls opening and dosing timing of an intake valve or an exhaust valve in an internal combustion engine by controlling a rotation phase between a driving shaft and a driven shaft. The valve timing controller includes a first housing, a second housing, a vane rotor, a sleeve, a spool and a reed valve. The first housing integrally rotates with the driving shaft and has a through hole through which the driven shaft passes. The second housing integrally rotates with the driving shaft and the first housing and has a pipe part and a bottom part. The first housing closes a first end of the pipe part, and the bottom part closes a second end of the pipe part. The vane rotor integrally rotates with the driven shaft and has a boss part and a vane part. The boss part is located inside the second housing. The vane part partitions inside of the second housing into an advance chamber and a retard chamber. The vane rotor rotates on an advance side or a retard side relative to the second housing based on a pressure of working oil in the advance chamber and the retard chamber. 
     A plurality of first supply passages is defined in the driven shaft and opens in an end surface of the driven shaft adjacent to the vane rotor. A plurality of second supply passages is defined in the vane rotor and opens in an end surface of the vane rotor adjacent to the first housing. The second supply passages respectively communicate with the first supply passages. 
     The sleeve has a cylindrical shape arranged on an inner side from the boss part in a radial direction. The sleeve has a supply port communicating with the second supply passage, an advance port communicating with the advance chamber, and a retard port communicating with the retard chamber. The spool slidably moves in the sleeve in an axial direction among an advance position at which the supply port is connected to the advance port, a retard position at which the supply port is connected to the retard port, and a shutoff position at which the supply port is shutoff from the advance port and the retard port. 
     The reed valve is interposed between the end surface of the vane rotor and the end surface of the driven shaft, and has a fixed part and a plurality of reed parts. The fixed part has a plurality of holes that respectively connect the first supply passages to the corresponding second supply passages. Each of the reed parts is formed to extend from an edge of the corresponding hole to cover the corresponding hole so as to open or close an open end of the corresponding first supply passage. The reed valve allows the working oil to flow from the first supply passage to the second supply passage and prohibits the working oil from flowing from the second supply passage to the first supply passage. 
     The plurality of reed parts includes at least a first reed part and a second reed part. Each of the first reed part and the second reed part has each lower limit pressure for allowing the working oil to flow from the first supply passage to the second supply passage. The lower limit pressure of the first reed part is different from the lower limit pressure of the second reed part. 
     Accordingly, the valve timing controller can accurately work even when a flow rate of working oil is varied. 
     Specifically, when the working oil flows with a small flow rate, which does not fill all the first supply passages and the second supply passage, at least one set of the first supply passage and the second supply passage are connected with each other to allow the working oil to flow. Thus, the working oil can be securely supply to the sleeve. When the working oil flows with a large flow rate, the working oil can be supplied to the sleeve using all the first supply passages and the second supply passage, so the valve timing of the intake valve or the exhaust valve can be quickly controlled. 
     According to an example of the present disclosure, a method of assembling the valve timing controller includes: attaching the reed valve to the first housing to agree with the through hole of the first housing; attaching the second housing, which receives the vane rotor inside, to the first housing; and inserting an end portion of the driven shaft into the through hole of the first housing in a manner that the reed valve is interposed between the end surface of the vane rotor and the end surface of the driven shaft. The attaching of the reed valve, the attaching of the second housing, and the inserting are conducted in this order. The second reed part before the inserting is inclined relative to the read valve toward the end surface of the driven shaft. 
     Accordingly, the valve timing controller can accurately work even when a flow rate of working oil is varied. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a schematic view illustrating a valve timing controller according to a first embodiment; 
         FIG. 2  is a schematic view illustrating an internal combustion engine having the valve timing controller; 
         FIG. 3  is a cross-sectional view taken along a line III-P 1 -P 2 -III of  FIG. 1 ; 
         FIG. 4  is a cross-sectional view taken along a line A 1 -P 3 -P 4 -P 5 -P 6 -P 7 -P 8 -P 9 -P 10 -P 11 -B of  FIG. 3 ; 
         FIG. 5A  is a schematic plan view illustrating a reed valve of the valve timing controller, and  FIG. 5B  is a cross-sectional view illustrating the reed valve; 
         FIG. 6  is an enlarged cross-sectional view of a section defined by a single chain line of  FIG. 1  in which a spool is located at an advance position; 
         FIG. 7  is an enlarged cross-sectional view of the section defined by a single chain line of  FIG. 1  in which a spool is located at a shutoff position; 
         FIG. 8  is an enlarged cross-sectional view of the section defined by a single chain line of  FIG. 1  in which a spool is located at a retard position; 
         FIG. 9A  is a schematic plan view illustrating a reed valve of a valve timing controller according to a second embodiment, and  FIG. 9B  is a side view illustrating the reed valve of the second embodiment; 
         FIG. 10  is a cross-sectional view illustrating a part of a valve timing controller according to a third embodiment; and 
         FIG. 11  is a cross-sectional view illustrating a part of a valve timing controller according to a fourth embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination. 
     (First Embodiment) 
     A valve timing controller  41  according to a first embodiment is used in a valve timing control system  40  shown in  FIG. 1 . The valve timing control system  40  controls opening and closing timing of an intake valve  12  of an internal combustion engine  10  shown in  FIG. 2 . The intake valve  12  is rotated by a camshaft  28 , and an exhaust valve  14  is rotated by a camshaft  26 . Rotation of a gear  18  of a crankshaft  16  of the engine  10  is transmitted to gears  20 ,  22  through a chain  24 . 
     The valve timing control system  40  advances the opening and closing timing of the intake valve  12  by rotating the camshaft  28  ahead in a rotation direction relative to the gear  22  rotating with the crankshaft  16 . 
     The valve timing control system  40  retards the opening and closing timing of the intake valve  12  by rotating the camshaft  28  opposite from the rotation direction relative to the gear  22  rotating with the crankshaft  16 . 
     The valve timing control system  40  is explained with reference to  FIGS. 1 ,  3  and  4 .  FIG. 1  is a cross-sectional view taken along a line A 1 -P 3 -P 4 -P 5 -P 6 -P 7 -P 8 -P 9 -A 2  of  FIG. 3 . As shown in  FIG. 1 , the valve timing control system  40  includes an oil pump  166 , a motor cylinder  172 , an electronic control unit (ECU)  176  in addition to the valve timing controller  41 . A double chain line L 1  of  FIG. 1  represents a flow of working oil from an oil pan  170  and the oil pump  166  to the valve timing controller  41 . A double chain line L 2  and a double chain line L 3  of  FIG. 1  represent a flow of working oil from the valve timing controller  41  to the oil pan  170 . 
     The valve timing controller  41  has a sprocket  45 , a shoe housing  58 , a front plate  70 , a vane rotor  74 , and a passage switching valve  130 . The sprocket  45  may correspond to a first housing. The shoe housing  58  may correspond to a pipe part. The front plate  70  may correspond to a bottom part. The shoe housing  58  and the front plate  70  may construct a second housing. 
     Rotation of the crankshaft  16  is transmitted to the gear  22  of the sprocket  45  through the chain  24 . The sprocket  45 , the shoe housing  58 , and the front plate  70  are integrally combined with each other, and integrally rotate with the crankshaft  16 . The sprocket  45 , the shoe housing  58 , and the front plate  70  define a rotor accommodation space that accommodates the vane rotor  74 . 
     The vane rotor  74  is integrally combined with the camshaft  28  by a lock pin  105 , and integrally rotates with the camshaft  28 . The rotor accommodation space has advance chambers  90 ,  92 ,  94 ,  96  (hereinafter referred as  90 - 96 ) and retard chambers  98 ,  100 ,  102 ,  104  (hereinafter referred as  98 - 104 ), and the vane rotor  74  receives pressure of working oil supplied to the advance chambers  90 - 96  or the retard chambers  98 - 104  so as to rotate on the advance side or the retard side relative to the shoe housing  58 . 
     The passage switching valve  130  switches supply passages  106 ,  107  inside of the vane rotor  74  to communicate with the advance chambers  90 - 96  or the retard chambers  98 - 104 . The vane rotor  74  has a convex portion  110 , and openings  128 ,  129  are defined in a tip end surface  112  of the convex portion  110 . The supply passage  106  communicates with a supply passage  30  defined inside of the camshaft  28  through the opening  128 . The supply passage  107  communicates with a supply passage  31  defined inside of the camshaft  28  through the opening  129 . The opening  128 ,  129  may correspond to a second supply passage. The passage switching valve  130  is operated by the motor cylinder  172 . 
     The oil pump  166  pumps working oil from the oil pan  170 , and supplies the working oil to the passage switching valve  130  via the supply passage  30 , the opening  128 , and the supply passage  106 . The working oil is supplied to the passage switching valve  130  also via the supply passage  31 , the opening  129 , and the supply passage  107 . That is, the valve timing controller  41  has two systems for supplying the working oil to the passage switching valve  130 . The supply passage  30 ,  31  may correspond to a first supply passage. 
     The motor cylinder  172  may be an electromagnetic type cylinder, and, as shown in  FIG. 1 , the motor cylinder  172  is attached to an engine cover  32 . The motor cylinder  172  is arranged to have the same axis as a spool  156  of the passage switching valve  130 . The motor cylinder  172  has a rod  174  and a solenoid (not shown). The rod  174  reciprocates in an axial direction. The solenoid is arranged on the outer side of the rod  174  in a radial direction. The rod  174  moves in the axial direction according to a magnetic field generated by the solenoid when the solenoid is energized. The rod  174  presses the spool  156  of the passage switching valve  130  in the axial direction. 
     The electronic control unit  176  drives the motor cylinder  172  in a manner that the rotation phase of the vane rotor  74  relative to the shoe housing  58  agrees with a target rotation phase. Specifically, when the rotation phase is on the retard side from the target rotation phase, the electronic control unit  176  controls the axial position of the spool  156  of the passage switching valve  130  in a manner that working oil is supplied to the advance chambers  90 - 96 . Moreover, when the rotation phase is on the advance side from the target rotation phase, the electronic control unit  176  controls the axial position of the spool  156  of the passage switching valve  130  in a manner that working oil is supplied to the retard chambers  98 - 104 . Moreover, when the rotation phase agrees with the target rotation phase, the electronic control unit  176  controls the axial position of the spool  156  of the passage switching valve  130  in a manner that the advance chambers  90 - 96  and the retard chambers  98 - 104  of the valve timing controller  41  are separated from the supply passage  106 ,  107  and a discharge passage. 
     The valve timing controller  41  will be specifically described. 
     The sprocket  45  integrally has an inner cylinder portion  46 , a flange portion  48  and an outer cylinder portion  50 . The inner cylinder portion  46  is fitted to an outer circumference wall of a first end part of the camshaft  28 . The flange portion  48  is projected from the inner cylinder portion  46  outward in the radial direction. The outer cylinder portion  50  extends from the outer circumference of the flange portion  48  toward a second end part of the camshaft  28 . The inner cylinder portion  46  has a through hole  52  through which the camshaft  28  passes. The outer cylinder portion  50  has the gear  22 . 
     The shoe housing  58  has a pipe part  60  and plural shoe parts  62 ,  64 ,  66 ,  68 . A first end of the pipe part  60  is closed by the sprocket  45 , and the plural shoe parts  62 ,  64 ,  66 ,  68  are projected inward in the radial direction from the pipe part  60 . The shoe parts  62 ,  64 ,  66 ,  68  are arranged to be distanced from each other in the circumference direction of the pipe part  60 . 
     The front plate  70  is a ring board member which doses a second end of the pipe part  60 . The sprocket  45 , the shoe housing  58 , and the front plate  70  are integrally combined with each other using plural bolts  72 . 
     The vane rotor  74  has a boss part  76  and plural vane parts  78 ,  80 ,  82 ,  84 . The boss part  76  is located on the inner side from the shoe parts  62 ,  64 ,  686 ,  68  in the radial direction, and the plural vane parts  78 ,  80 ,  82 ,  84  are projected outward in the radial direction from the boss part  76 . The vane rotor  74  is rotated relative to the sprocket  45 , the shoe housing  58 , and the front plate  70 . 
     The boss part  76  has a first fitting hole  86  to which a sleeve part  134  of a sleeve bolt  132  is fitted. A center washer  88  is fitted to the boss part  76  at a position opposing to the front plate  70 . The vane rotor  74  and the camshaft  28  are integrally combined with each other by the sleeve bolt  132  which passes through the center washer  88  and the vane rotor  74  to be tightened to the camshaft  28 . 
     Four vane accommodation chambers are defined between the boss part  76  of the vane rotor  74  and the pipe part  60  of the shoe housing  58 , and are divided by the shoe parts  62 ,  84 ,  66 ,  68 . Each of the vane accommodation chambers accommodates the vane part  78 ,  80 ,  82 ,  84  in a manner that the vane part  78 ,  80 ,  82 ,  84  is relatively rotatable within a predetermined angle range. In  FIG. 3 , a clockwise rotation direction represents an advance direction, and a counterclockwise rotation direction represents a retard direction. The vane accommodation chamber is divided into the advance chamber  90 ,  92 ,  94 ,  96  and the retard chamber  98 ,  100 ,  102 ,  104  by the vane part  78 ,  80 ,  82 ,  84 . 
     The vane part  78  of the vane rotor  74  has a receiving hole  108  penetrated in the axial direction as a through hole. The receiving hole  108  has a first part adjacent to the front plate  70  and a second part adjacent to the sprocket  45 , and an inside diameter of the first part is larger than that of the second part through a step part. A lock pin  116  is received in the receiving hole  108  in a manner that the lock pin  116  reciprocates in the axial direction. The lock pin  116  is slidably movable relative to an inner wall of the second part of the receiving hole  108 , and has a flange  118  projected outward in the radial direction inside of the first part of the receiving hole  108 . The lock pin  116  is biased toward the sprocket  45  by a first spring  120  that is arranged adjacent to the front plate  70 . 
     When the vane rotor  74  is located at an optimal position optimal for an engine start, the lock pin  116  is able to be fitted to a fitting concave portion  54  defined in the sprocket  45  adjacent to the vane rotor  74 . The lock pin  116  regulates the relative rotation of the vane rotor  74  relative to the shoe housing  58  by fitting to the fitting concave portion  54  at the optimal position. In the first embodiment, the optimal position is set as the maximum retard position of the vane rotor  74 , and the fitting concave portion  54  is formed to correspond to the lock pin  116  in a case where the vane rotor  74  is located at the maximum retard position. 
     A first unlock chamber  122  is defined to extend from the flange  118  of the lock pin  116  toward the sprocket  45 . The first unlock chamber  122  is communicated with the advance chamber  90  via a passage (not shown). Moreover, a second unlock chamber  126  is defined between the lock pin  116  and the sprocket  45 . The second unlock chamber  126  is communicated with the retard chamber  98  via a passage (not shown). 
     The pressure of the working oil supplied to the first unlock chamber  122  through the advance chamber  90  and the pressure of the working oil supplied to the second unlock chamber  126  through the retard chamber  98  act in a manner that the lock pin  116  comes out of the fitting concave portion  54 . It is determined by a balance between the biasing force of the first spring  120  and the difference in the pressure of the working oil between the first unlock chamber  122  and the second unlock chamber  126  whether the vane rotor  74  is held at the optimal position by the lock pin  116 . 
     The passage switching valve  130  has the sleeve bolt  132  and the spool  156 . The sleeve bolt  132  integrally has the sleeve part  134 , a thread part  136 , and a head part  138  as a sleeve. The sleeve part  134  has a cylindrical shape, and is fitted with the first fitting hole  86  of the boss part  76  of the vane rotor  74  by passing through the center washer  88 . The sleeve part  134  has a supply port  140 , an advance port  144  and a retard port  148 . The supply port  140  communicates with the supply passages  106 ,  107 . The advance port  144  communicates with the advance chambers  90 - 96  via an advance passage  142  defined inside of the vane rotor  74 . The retard port  148  communicates with the retard chambers  98 - 104  via a retard passage  146  defined inside of the vane rotor  74 . 
     The supply port  140  is defined, for example, at four positions arranged in the circumference direction, and communicates with the supply passage  106 ,  107  via a first annular groove  150  defined in the inner wall of the first fitting hole  86 . Moreover, the advance port  144  is defined, for example, at four positions arranged in the circumference direction, and communicates with the advance passage  142  via a second annular groove  152  defined in the inner wall of the first fitting hole  86 . Moreover, the retard port  148  is defined, for example, at four positions arranged in the circumference direction, and communicates with the retard passage  146  via an annular oil passage  154  defined on the inner side from the center washer  88  in the radial direction. 
     The thread part  136  extends toward the camshaft  28  from the sleeve part  134 , and is coupled to a tapped hole  36  defined in an end surface  34  of the camshaft  28 . 
     The head part  138  has a cylindrical shape having the same axis as the sleeve part  134 . The sleeve part  134  is located between the thread part  136  and the head part  138 . The head part  138  has an outside diameter larger than that of the sleeve part  134 . 
     The spool  156  is located on the inner side from the sleeve part  134  and the head part  138  in the radial direction. The spool  156  has a cylindrical shape having the same axis as the sleeve part  134 . The spool  156  is slidably movable relative to the inner wall of the sleeve part  134  in the axial direction. The spool  158  is biased toward the front plate  70  by a second spring  157  which is arranged adjacent to the sprocket  45 . The axial position of the spool  156  is determined by a balance between the biasing force of the second spring  157  and the thrust force of the rod  174  of the motor cylinder  172 . 
       FIG. 6  illustrates the spool  156  located at an advance position. The spool  156  is made to contact the thread part  136 . The spool  156  located at the advance position connects the supply port  140  to the advance port  144 , and disconnects the supply port  140  from the retard port  148 . At this time, the working oil of the retard chambers  98 - 104  is discharged outside via the retard passage  146 , the annular oil passage  154 , the retard port  148 , and a passage  160  defined between the sleeve bolt  132  and the spool  156 . The passage  160  may be equivalent to the above-mentioned discharge passage. 
       FIG. 7  illustrates the spool  156  located at a shutoff position. The radially outer surface of the spool  156  located at the shutoff position closes the advance port  144  and the retard port  148 , thereby shutting off the supply port  140  of the sleeve part  134  from the advance port  144  and the retard port  148 . 
       FIG. 8  illustrates the spool  156  located at a retard position. The spool  156  is made to contact a stopper plate  196  that is fitted to the inner wall of the head part  138 . The spool  156  located at the retard position connects the supply port  140  to the retard port  148 , and disconnects the supply port  140  from the advance port  144 . At this time, the working oil of the advance chambers  90 - 96  is discharged outside via the advance passage  142 , the advance port  144 , a hole  162  of the spool  156 , and a radially inside passage  164  of the spool  156 . The hole  162  and the radially inside passage  164  may be equivalent to the above-mentioned discharge passage. 
     The valve timing controller  41  includes a reed valve  178  which is described with reference to  FIGS. 4 ,  5 A and  5 B. 
     The reed valve  178  is arranged between the end surface  112  of the convex portion  110  of the vane rotor  74  and the end surface  34  of the camshaft  28 . The reed valve  178  has a fixed part  182 , a first reed part  184  and a second reed part  185 . The fixed part  182  has a first hole  180 , a second hole  181  and a through hole  183 . The supply passage  31  and the opening  129  are communicated with each other through the first hole  180 . The supply passage  30  and the opening  128  are communicated with each other through the second hole  181 . The sleeve part  134  passes through the through hole  183 . The first reed part  184  extends inside of the first hole  180  to cover the first hole  180  from the edge of the first hole  180 . The second reed part  185  extends inside of the second hole  181  to cover the second hole  181  from the edge of the second hole  181 . 
     The reed valve  178  is a check valve which allows the working oil to flow from the supply passage  30 ,  31  to the opening  128 ,  129  and prohibits the working oil from flowing from the opening  128 ,  129  to the supply passage  30 ,  31 . 
     The first reed part  184  integrally has a first lid part  186  and a first flexible part  188 . The lid part  186  closes the supply passage  31  defined in the end surface  34 . The flexible part  188  connects the lid part  186  to the fixed part  182 . When the pressure of the working oil in the supply passage  31  acts on the lid part  186 , the flexible part  188  bends in a manner that the lid part  186  is distanced from the open end of the supply passage  31 . 
     The second reed part  185  integrally has a second lid part  187  and a second flexible part  189 . The lid part  187  closes the supply passage  30  defined in the end surface  34 . The flexible part  189  connects the lid part  187  to the fixed part  182 . When the pressure of the working oil in the supply passage  30  acts on the lid part  187 , the flexible part  189  bends in a manner that the lid part  187  is distanced from the open end of the supply passage  30 . 
     At this time, a dimension D 2  from the center of the second lid part  187  to a connection point at which the second flexible part  189  and the fixed part  182  are connected with each other is larger than a dimension D 1  from the center of the first lid part  186  to a connection point at which the first flexible part  188  and the fixed part  182  are connected with each other. That is, a pressure necessary for opening the second reed part  185  is smaller than that for opening the first reed part  184 . The pressure necessary for opening the reed part may correspond to a lower limit pressure for allowing the working oil to flow from the first supply passage to the second supply passage. 
     Next, procedure assembling components to produce the valve timing controller  41  and procedure fixing the valve timing controller  41  to the engine  10  are explained. The procedure manufacturing the valve timing controller  41  is explained with reference to  FIGS. 1 and 4  which illustrate a finished product, for convenience. 
     The lock pin  116 , the first spring  120 , and a spring receptacle component  194  are attached to the vane rotor  74  at first. The spring receptacle component  194  is pressingly fitted into the vane rotor  74 . 
     The reed valve  178  is arranged in the concave portion  56  of the sprocket  45 . The vane rotor  74 , the shoe housing  58 , and the front plate  70  are arranged to the sprocket  45  in a manner that the convex portion  110  of the vane rotor  74  is fitted with the concave portion  56  of the sprocket  45 , and are fastened using the bolt  72 . 
     Then, as shown in  FIG. 4 , the center washer  88  is fitted into the center section of the vane rotor  74 , and a control pin (not shown) is pressingly fitted, for example. 
     The second spring  157 , the spool  156 , and the stopper plate  196  are arranged in the sleeve bolt  132 , and a snap ring  198  is fitted with the inner wall of the head part  138 , so as to restrict the spool  156  from slipping off. Thus, the assembling of the valve timing controller  41  is completed. 
     Thereafter, the valve timing controller  41  is attached to the engine  10 . The end portion of the camshaft  28  is inserted into the through hole  52  of the sprocket  45 , at first. 
     Then, the valve timing controller  41  is fixed to the camshaft  28  with the sleeve bolt  132 , thus the valve timing controller  41  is completely attached to the engine  10 . 
     Next, operation of the valve timing controller  41  will be explained in detail. 
     When the rotation phase of the vane rotor  74  relative to the shoe housing  58  is on the retard side from a target rotation phase, the spool  156  of the passage switching valve  130  is moved to the advance position shown in  FIG. 6 . As shown in  FIG. 1 , the working oil is supplied from the oil pump  166  via the supply passage  30 ,  31 , the opening  128 ,  129 , the supply passage  106 ,  107  and the first annular groove  150 , to the supply port  140 . The supplied oil flows into the advance chambers  90 ,  92 ,  94 ,  96  via the advance port  144  and the advance passage  142 . On the other hand, the working oil of the retard chambers  98 ,  100 ,  102 ,  104  is discharged outside via the retard passage  146 , the retard port  148 , and the passage  160 . Thus, the vane rotor  74  is advanced relative to the shoe housing  58 . 
     Moreover, when the rotation phase of the vane rotor  74  relative to the shoe housing  58  is on the advance side from a target rotation phase, the spool  156  of the passage switching valve  130  is moved to the retard position shown in  FIG. 8 . As shown in  FIG. 1 , the working oil is supplied from the oil pump  166  via the supply passage  30 ,  31 , the opening  128 ,  129 , the supply passage  106 ,  107  and the first annular groove  150 , to the supply port  140 . The supplied oil flows into the retard chambers  98 ,  100 ,  102 ,  104  via the retard port  148  and the retard passage  146 . On the other hand, the working oil of the advance chambers  90 ,  92 ,  94 ,  96  is discharged outside via the advance passage  142 , the advance port  144 , the hole  162  and the passage  164 . Thereby, the vane rotor  74  is retarded relative to the shoe housing  58 . 
     Moreover, when the rotation phase of the vane rotor  74  relative to the shoe housing  58  is in agreement with a target rotation phase, the spool  156  of the passage switching valve  130  is moved to the shutoff position shown in  FIG. 7 . At this time, the advance chambers  90 ,  92 ,  94 ,  96  are separated from the supply port  140  and the passage  164 , and the retard chambers  98 ,  100 ,  102 ,  104  are separated from the supply port  140  and the passage  180 . Thereby, the working oil stays in the advance chambers  90 ,  92 ,  94 ,  96  and the retard chambers  98 ,  100 ,  102 ,  104 . As a result, the relative position of the vane rotor  74  does not change relative to the shoe housing  58 . 
     When the working oil is supplied to the passage switching valve  130 , the flow rate of the working oil supplied from the supply passage  30 ,  31  to the supply passage  106 ,  107  through the opening  128 ,  129  is fluctuated because the amount of the working oil discharged from the oil pump  16688  fluctuates periodically. The reed valve  178  restricts the working oil from flowing backward to the supply passage  30 ,  31  from the opening  128 ,  129 . Thereby, the pressure of the working oil of the supply passage  106 ,  107 , which communicates with the opening  128 ,  129 , is restricted from declining while the working oil is supplied to each chamber. Therefore, the pressure of the working oil can be quickly raised in each chamber. 
     When working oil with a small flow rate is supplied to the supply passage  30 ,  31 , the second reed part  185  is opened earlier than the first reed part  184  because the dimension D 2  of the second flexible part  189  of the second reed part  185  is longer than the dimension D 1  of the first flexible part  188  of the first reed part  184 . Thereby, working oil is supplied to the passage switching valve  130 , and the opening and closing timing of the intake valve  12  is controlled. 
     Moreover, when working oil with a large flow rate is supplied to the supply passage  30 ,  31 , both of the first reed part  184  and the second reed part  185  are opened. Thereby, working oil is supplied to the passage switching valve  130 , and the opening and closing timing of the intake valve  12  is controlled. 
     According to the first embodiment, the valve timing controller  41  has two supply passages (systems) which supply working oil to the passage switching valve  130 . The reed valve  178  has the first reed part  184  and the second reed part  185  to correspond to the two supply passages. Because the dimension D 2  is longer than the dimension D 1 , the spring constant of the second reed part  185  is smaller than the spring constant of the first reed part  184 . 
     When working oil of a small flow rate is supplied, the second reed part  185  is opened earlier than the first reed part  185  because the spring constant of the second reed part  185  is smaller, and working oil is supplied to the passage switching valve  130 . On the other hand, when working oil of a large flow rate is supplied, both of the first reed part  184  and the second reed part  185  are opened and working oil is supplied to the passage switching valve  130 . 
     Thus, in the valve timing controller  41  of the first embodiment, when working oil of a large flow rate is supplied, the passage switching valve  130  can be maintained to have high switching speed for the passages. In contrast, when working oil of a small flow rate is supplied, the second reed part  185  having the small spring constant is opened, thereby working oil can be supplied to the passage switching valve  130  with reliability. 
     (Second Embodiment) 
     A second embodiment will be described with reference to  FIGS. 9A and 9B . A reed valve  278  of the second embodiment is different from the reed valve  178  of the first embodiment. The substantially same parts and components as the first embodiment are indicated with the same reference numeral and the same description will not be reiterated. 
       FIG. 9A  illustrates a plan view of the reed valve  278  used for the valve timing controller of the second embodiment.  FIG. 9B  illustrates a side view of the reed valve  278  before being mounted to the valve timing controller. 
     The reed valve  278  of the second embodiment has two reed parts, similarly to the reed valve  178  of the first embodiment. The reed valve  278  has a fixed part  282 , a first reed part  284  and a second reed part  285 . The fixed part  282  has a first hole  280  and a second hole  281 . The first reed part  284  extends to cover the first hole  280  from the edge of the first hole  280 . The second reed part  285  extends to cover the second hole  281  from the edge of the second hole  281 . 
     The first reed part  284  integrally has a first lid part  286  and a first flexible part  288  which connects the first lid part  286  to the fixed part  282 . Moreover, the second reed part  285  integrally has a second lid part  287  and a second flexible part  289  which connects the second lid part  287  to the fixed part  282 . 
     A dimension D 22  from the center of the second lid part  287  to a connection point at which the second flexible part  289  and the fixed part  282  are connected with each other is larger than a dimension D 21  from the center of the first lid part  286  to a connection point at which the first flexible part  288  and the fixed part  282  are connected with each other. 
     The first reed part  284  is not located in the same plane as the fixed part  282  before the reed valve  278  is attached to the valve timing controller, that is, when the reed valve  278  is in the free state. Specifically, as shown in  FIG. 9B , the first reed part  284  is formed to be inclined relative to a flat surface  341  of the reed valve  278 . 
     A method of assembling the valve timing controller of the second embodiment will be described. Similarly to the first embodiment, in a first process, the reed valve  278  is arranged in the concave portion  56  of the sprocket  45 . At this time, the reed valve  278  is attached in a manner that the opposite surface of the reed valve  278  opposite from the flat surface  341  will contact the tip end surface  112  of the vane rotor  74  in the following process. 
     Next, in a second process, the vane rotor  74 , the shoe housing  58 , and the front plate  70  are attached to the sprocket  45  in a manner that the convex portion  110  of the vane rotor  74  is fitted into the concave portion  56  of the sprocket  45 , and are fastened with the bolt  72 . 
     Then, the center washer  88  is inserted into the center section of the vane rotor  74 , and the second spring  157 , the spool  156 , and the stopper plate  196  are arranged in the sleeve bolt  132 . The snap ring  198  is fitted with the inner wall of the head part  138  so as to restrict the spool  156  from slipping off. 
     Next, in a third process, the end portion of the camshaft  28  is inserted into the through hole  52  of the sprocket  45 . At this time, the reed valve  278  is interposed between the tip end surface  112  of the vane rotor  74  and the end surface  34  of the camshaft  28 . Moreover, the flat surface  341  of the reed valve  278  is contacted with the end surface  34  of the camshaft  28 , and the first reed part  284  is pressed into the same plane as the reed valve  278 . 
     Then, the valve timing controller of the second embodiment is fixed to the camshaft  28  with the sleeve bolt  132 , thus the attachment of the valve timing controller to the engine  10  is completed. 
     According to the second embodiment, the first reed part  284  is formed to be inclined toward the end surface  34  of the camshaft  28  before inserted between the tip end surface  112  and the end surface  34 . Therefore, the spring constant of the first reed part  284  becomes larger than that the second reed part  285 , so the pressure necessary for opening the first reed part  284  is larger that that for opening the second reed part  285 . When working oil flows through the supply passages  30 ,  31 , the second reed part  285  opens earlier than the first reed part  284 , because the pressure necessary for opening the second reed part  285  is relatively smaller, and working oil is supplied to the passage switching valve  130 . Therefore, the same advantages can be obtained in the second embodiment as the first embodiment. 
     (Third Embodiment) 
     A valve timing controller  43  according to a third embodiment will be described with reference to  FIG. 10 . In the third embodiment, compared with the first embodiment, the inside diameter R 2  of the opening  128  is made different from the inside diameter R 1  of the opening  129 . The substantially same parts and components as the first embodiment are indicated with the same reference numeral and the same description will not be reiterated. 
     In the valve timing controller  43  of the third embodiment, the Inside diameter R 2  of the opening  128  corresponding to the second reed part  185  is made smaller than the inside diameter R 1  of the opening  129  corresponding to the first reed part  184 . That is, the cross-sectional area of the opening  128  is smaller than the cross-sectional area of the opening  129 . 
     The reed part  184 ,  185  is opened or closed according to the difference in the pressure of the working oil between the supply passage  30 ,  31  and the opening  128 ,  129 . When the same quantity of working oil flows through the supply passages  30  and  31 , the flow velocity of the working oil which flows through the opening  128  becomes high compared with the flow velocity of the working oil which flows through the opening  129 . 
     Thereby, a variation in the flow velocity of the working oil before and after the second reed part  185  becomes larger than a variation in the flow velocity of the working oil before and after the first reed part  184 , therefore a pressure difference before and after the reed part becomes large in the second reed part  185  compared with the first reed part  184 . Thus, the second reed part  185  is opened earlier than the first reed part  184 , and the same advantages can be obtained as the valve timing controller  41  of the first embodiment. 
     (Fourth Embodiment) 
     A valve timing controller  44  according to a fourth embodiment will be described with reference to  FIG. 11 . In the fourth embodiment, compared with the first embodiment, the inside diameter R 4  of the supply passage  30  is made different from the inside diameter R 3  of the supply passage  31 . The substantially same parts and components as the first embodiment are indicated with the same reference numeral and the same description will not be reiterated. 
     In the valve timing controller  44  of the fourth embodiment, the inside diameter R 4  of the supply passage  30  corresponding to the second reed part  185  is made larger than the inside diameter R 3  of the supply passage  31 . That is, the cross-sectional area of the supply passage  30  is larger than the cross-sectional area of the supply passage  31 . 
     The reed part  184 ,  185  is opened or closed according to the difference in the pressure of the working oil between the supply passage  30 ,  31  and the opening  128 ,  129 . When the same quantity of working oil flows through the supply passages  30  and  31 , the amount of working oil flowing through the supply passage  30  is larger than the amount of working oil flowing through the supply passage  31 . 
     Because higher pressure is applied to the second reed part  185  and because the pressure necessary for opening the second reed part  185  is smaller compared with the first reed part  184 , the second reed part  185  is opened quickly, and working oil flows into the sleeve part  134  through the opening  128  and the supply passage  106 . Therefore, the same advantages can be obtained as the valve timing controller  41  of the first embodiment. 
     (Other Embodiments) 
     In the above embodiments, the camshaft  28  has two supply passages  30 ,  31 , and the vane rotor  74  has two openings  128 ,  129  and two supply passages  106 ,  107 . However, the number of the supply passages or the openings is not limited to two, and may be more than two. In this case, the number of the reed parts formed in the reed valve is set to correspond to the number of the supply passages or the openings. 
     In the third embodiment, the inside diameter R 2  of the opening  128  corresponding to the second reed part  185  is smaller than the inside diameter R 1  of the opening  129  corresponding to the first reed part  184 . However, the size relationship of the openings  128 ,  129  is not limited, while the cross-sectional area of the opening  128  corresponding to the second reed part  185  is smaller than the cross-sectional area of the opening  129  corresponding to the first reed part  184 . 
     In the fourth embodiment, the inside diameter R 4  of the supply passage  30  corresponding to the second reed part  185  is larger than the inside diameter R 3  of the supply passage  31  corresponding to the first reed part  184 . However, the size relationship of the supply passages  30 ,  31  is not limited, while the cross-sectional area of the supply passage  30  corresponding to the second reed part  185  is larger than the cross-sectional area of the supply passage  31  corresponding to the first reed part  184 . 
     The present disclosure is not limited to the above embodiments. 
     Such changes and modifications are to be understood as being within the scope of the present disclosure as defined by the appended claims.