Abstract:
The vane type hydraulic actuator in the prior art has a drawback that the locking of the rotor at a best position was difficult, therefore, the optimization of the timing of opening and closing of the valves, using a simple apparatus, was impossible.  
     The vane type hydraulic actuator according to the present invention comprises a guide locking means (guide stopper pin) ( 1 ) for guiding the rotor ( 44 ) to a locking position where the rotor ( 44 ) can be locked to the case ( 43 ), and a retaining locking means (retaining stopper pin) ( 4 ) for retaining the rotor ( 44 ) to the case ( 43 ), after the rotor ( 44 ) is guided to the locking position.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the invention  
           [0002]    The present invention relates to a vane type hydraulic actuator for controlling the timing of opening and closing of an intake and/or exhaust valve, corresponding to an operational state of an engine.  
           [0003]    2. Description of the prior art  
           [0004]    [0004]FIG. 18 is a cross sectional view of a vane type hydraulic actuator invented by the inventors of this application and is disclosed in JP-9-314069-A. FIG. 19 is a detailed cross sectional view of the plunger part shown in FIG. 18. FIG. 20 is a cross sectional view of the plunger part in a state that a hydraulic pressure is applied.  
           [0005]    Reference numeral  19  denotes an intake side cam shaft having an intake side cam  19   a . An actuator  40  is connected to an end of the intake side cam shaft  19 , and a timing pulley  21  is disposed around the actuator  40 . The working oil of the actuator  40  is lubrication oil, delivered from an engine (not shown). The actuator is actuated by the working oil so as to adjust phase angle of the rotation of the intake side cam shaft  19  so that the opening and closing timings of intake valves of the engine can be continuously adjusted. The intake side cam shaft  41  is supported by a bearing  19 . The actuator  40  has a housing  42 , which can freely rotate around the intake side cam shaft  19 .  
           [0006]    A case  43  is fixed to the housing  42 . And a vane type rotor  44  is received in the case  43 . The vane rotor  44  is fixed to the intake side cam shaft  19  by means of bolts  45 . The rotor  44  is rotatable relative to the case  43  in a predetermined anglular region.  
           [0007]    The case  43  and the rotor  44  form hydraulic pressure chambers separated from each other. A chip seal  46  is disposed between the case  43  and the rotor  44  so that no oil leakage between the oil pressure chambers can occur. A back spring  47  made of an iron plate is disposed to push the chip seal  46  towards the rotor  44 .  
           [0008]    The housing  42 , the case  43  and a cover  48  connected to the case  43  are fixed by a common volt  49 . An O-ring  50  is disposed between the case  43  and the bolt  50 . A plate  51  is fixed to the cover  48  by a bolt  52 . Reference numerals  53 ,  54  denote O-rings. A cylindrical holder  55  is disposed in the rotor  44 . The cylindrical holder  55  has an engaging hole  55   a , which can engage with a plunger  56 , as will be explained below.  
           [0009]    The plunger  56  disposed in the housing  42  can slide therein and has an engaging shaft  56   a , which can engage with the engaging hole  55   a  of the holder  55 . The plunger  56  is pushed by a spring  57  towards the holder  55 . Working oil is delivered into the engaging hole  55   a  of the holder  55  through a plunger oil channel  58 . When working oil is delivered into the engaging hole  55   a  of the holder  55 , the plunger  56  moves opposingly to the spring  57  so that the plunger  56  is unlocked from the holder  55 . The rotor  44  is fixed to the intake side cam shaft  19  by means of a bolt  60 . Reference numerals  59 ,  61  denote air holes.  
           [0010]    A first and second oil channels  62 ,  63  are disposed in the intake side cam shaft  19  and the rotor  44 . The first oil channel  62  communicates with an oil pressure chamber for timing retard  73 , and the second oil channel  63  communicates with an oil pressure chamber for timing advance  74 .  
           [0011]    The amount of the working oil to be delivered to the actuator  40  is controlled by an oil control valve  80 , which will be abbreviated to OCV hereinafter.  
           [0012]    The OCV  80  comprises a valve housing  81 , a spool  82  which can slide in the valve housing  81 , a spring  83  urging the spool  82  toward one direction, and a linear solenoid  84  for displacing the spool  82  resisting the spring  83 . The OCV is connected with an oil pan  91  through an oil supplying pipe  85   a . An oil pump  92  and an oil filter  93  are disposed in the oil supplying pipe  85   a . The first and second oil channels  62 ,  63  are connected with the OCV  80  through a first and second oil pipes  89 ,  90 , respectively. The working oil returns to the oil pan  91  from the OCV  80  through an oil drain pipe  88 . The oil pan  91 , the oil pump  92 , the oil filter  93  are a part of a lubrication system for lubricating portions to be lubricated in the engine (not shown), and simultaneously they form a working oil delivery system to the actuator  40 .  
           [0013]    An electronic control unit  100 , which is abbreviated to ECU hereinafter, controls the amount of fuel injection into the engine, the timings of the ignition, and the timing of the opening and closing of valves. The control corresponds to the inputs from an intake air amount sensor, a throttle sensor, crank angle sensor and a cam angle sensor, which are not shown. The electronic control unit  100  further controls the closing timing of valves after the switching off of the ignition switch.  
           [0014]    [0014]FIG. 21 is a cross sectional view of FIG. 18 along the line X-X. FIG. 22 shows a state in which a slide plate shown in FIG. 21 is displaced. FIG. 23 is a cross sectional view of FIG. 18 along the line Y-Y, FIG. 24 is a cross sectional view of FIG. 18 along the line Z-Z.  
           [0015]    As shown in the figures, a first to fourth vanes  64 - 67  project radially from the rotor  44 . A chip seal  68  is disposed at the tip of each vane  64 - 67 . The chip seal  68  contacts with the inner surface of the case  43  and can slide along the surface. The chip seals  68  seal between the chambers disposed at both sides of the vanes. By the way, a back spring (not shown) is disposed behind each chip seals  68  for increasing the capacity of the sealing.  
           [0016]    Four shoes  71  project inwardly from the inner surface of the case  43 . The shoe  43  has a bolt hole  72 , into which the bolt  49  shown in FIG. 18 is screwed.  
           [0017]    The tip portion of each shoe  71  contacts with a vane supporting portion  69  of the rotor, namely the hub of the rotor, which supports the vanes. The tip portion of each shoe  71  slides along the outer surface of the vane supporting portion  69 . Each room between the adjacent shoes  71  is divided by the corresponding shoe  71  into an oil pressure chamber for timing retard  73  and an oil pressure chamber for timing advance  74 . These chambers  73 ,  74  are formed alternatively and have a form of a sector like room contoured peripherally by the inner surface of the case  43  and the outer surface of the rotor  44  and contoured radially by one of the shoes  71  and one of the vanes  64 - 67  of the rotor  44 .  
           [0018]    The oil pressure chamber for timing retard  73  is used for swing the first to fourth vanes  64 - 67  so that the timing of the opening and closing of valves is retarded. And the oil chamber for timing advance  74  is used for swing the first to fourth vanes  64 - 67  so that the timing of the opening and closing of valves is advanced.  
           [0019]    The oil pressure chamber for timing retard  73  and the oil pressure chamber for timing advance  74  disposed at both side of the first vane  64  are communicated through a communicating channel  75 , which passes through the first vane  64 . A groove  76  is disposed in the communicating channel  75 , and the plunger oil channel  58  communicates with the groove  76 .  
           [0020]    A slide plate  77  is disposed in the groove  76 . The slide plate  77  divides the communicating channel  75  into two parts in such a manner that the oil leakage between the oil pressure chamber for timing retard  73  and the oil pressure chamber for timing advance  74  is prevented.  
           [0021]    The slide plate  77  moves toward the oil pressure chamber for timing advance  74 , when the oil pressure in the oil pressure chamber for timing retard  73  is higher. It moves towards the oil chamber for timing retard  73 , when the pressure in the oil pressure chamber for timing advance  74  is higher. The arrow marks in FIGS. 21, 23,  24  show the rotation direction of the actuator  40  as a whole.  
           [0022]    The oil pressure chambers for timing retard and advance  73 ,  74  are surrounded by the housing  42 , case  43 , rotor  44  and cover  48 . The oil pressure chamber for timing retard  73  communicates with the first oil channel  62  so that working oil is delivered to the chamber  73  through the first oil channel  62 . And the oil pressure chamber for timing advance  74  communicates with the second oil channel  63  so that working oil is delivered to the chamber  74  through the second oil channel  63 . The rotor  44  rotates relatively to the housing  42 , when the volumes of the oil pressure chambers  73 ,  74  change, corresponding to the amount of working oil delivered to each of the oil pressure chambers  73 ,  74   
           [0023]    The function of the actuator  40  and the OCV  80  is explained below.  
           [0024]    At first, when the engine is stopping, the rotor  44  is positioned, as shown in FIG. 21, at the maximum timing advance position, namely, the rotor  44  has rotated at most in the timing advance direction. Also the oil pump  92  is stopping, therefore, no working oil is delivered either to the first and second oil channels  62 ,  63 , as a result, no working oil is supplied to the plunger oil channel  58 . Consequently, the oil pressure in the actuator  40  is low. As a result, the plunger  56  is pushed by the urging force of the spring  57  towards the holder  55  so that the engaging shaft  56   a  of the plunger  56  engages with the engaging hole  55   a  of the holder  55 , that is to say, the rotor  44  is locked to the housing  42 .  
           [0025]    In this specification and claims, a “timing advance direction” is a rotation direction of the rotor relative to the housing to advance the timing of the opening and closing of the valves, and a “timing retard direction” is a rotation direction of the rotor relative to the housing to retard the timing of the opening and closing of the valves.  
           [0026]    Starting from this state, when the engine is started, the oil pump  92  functions to increase the oil pressure to the OCV  80  so that working oil is delivered through the first oil pipe  89  and the first oil channel  62  to the oil pressure chamber for timing retard  73  in the actuator  40 . Due to the high oil pressure in the oil pressure chamber for timing retard  73 , the slide plate  77  moves towards the oil pressure chamber for timing advance  74 . As a result, the oil pressure chamber for timing retard  73  communicates with the plunger oil channel  58  so that the working oil is delivered through this plunger oil channel  58  into the engaging hole  55   a  of the holder  55 . As a result, the plunger  56  is urged toward the spring, resisting the spring force, so that the engaging shaft  56   a  of the plunger  56  is pushed out from the engaging hole  55   a  of the holder  55   a . That is to say, the engaging or locking between the plunger  56  and the rotor  44  is released.  
           [0027]    Also in this state, due to the working oil delivered into the oil pressure chamber for timing retard, each vane  65 - 67  of the rotor  44  is pressed to a shoe  71  from the oil pressure chamber  73 , and contacts with a flank of the shoe  71 . Therefore, even in the unlocked state between the plunger  56  and the rotor  44 , the housing  42  and the rotor  44  are pressing to each other due to the oil pressure in the oil pressure chamber for timing retard  73 . As a result, the vibration or clashing in the actuator can be reduced or eliminated.  
           [0028]    For changing the opening and closing timing of the valves, working oil is delivered from the OCV  80  to the oil chamber for timing advance  74  through the second oil pipe  90  and the second oil channel  63 . The oil pressure in the oil chamber for timing advance  74  is delivered to the communicating channel  75  so that the slide plate  77  is pushed to move towards the oil pressure chamber for timing retard  73 . Due to this movement of the slide plate  77 , the plunger oil channel  58  communicates with the communicating channel  75  at the oil pressure chamber for timing advance  74  side so that the oil pressure in the oil pressure chamber for timing advance  74  is supplied to the plunger oil channel  58 . Due to this high oil pressure, the plunger  56  moves towards the housing  42  resisting the force of the spring  57 , so that the engaging or locking between the plunger  56  and the holder  55  is released.  
           [0029]    In this unlocked state, the opening and closing of the OCV  80  is controlled so as to control the oil delivery to the oil pressure chambers for timing retard and advance  73 ,  74  so that the rotation angle of the rotor  44  relative to the rotation angle of the housing  42  is changed, that is to say, the rotor  44  is rotated in the timing advance direction or in the timing retard direction. For example, when the rotor  44  is rotated at most in the timing advance direction, the rotor rotates at a state that each vane  64 - 67  of the rotor  44  is contacting with a shoe  71  from the oil pressure chamber for timing retard  73  side, as shown in FIG. 22. When the oil pressure in the oil pressure chamber for timing retard  73  is higher than that in the oil pressure chamber for timing advance  74 , the rotor  44  rotates in the timing retard direction relatively to the housing  42 .  
           [0030]    As explained above, the rotor  44  is controlled to rotate relatively to the housing  42  in the timing advance direction or in the timing retard direction, by adjusting the oil delivery to the oil pressure chambers for timing advance and retard  73 ,  74 . The oil leakage at the oil delivery between the oil pressure chambers  73 ,  74  is prevented by means of chip seals  46 ,  68 .  
           [0031]    By the way, the oil pressure provided from the OCV  80  is controlled by the ECU  100 , corresponding to the outputs from a position sensor, which detects the rotation angel of the rotor  44  relative to the housing  42 , and a crank angle sensor, which determines the pressure to be supplied from the oil pump  92 .  
           [0032]    Another apparatus for adjusting the timings of the opening and closing of valves in an internal combustion engine using a vane type hydraulic actuator is disclosed in JP-9-60507-A, which employs a structure that one stopper pin, as a locking means, locks the rotor in the maximum timing retard position or in the maximum timing advance position, while the timings of the opening and closing of valves are adjusted at the starting of the engine.  
           [0033]    As explained above, vane type actuators in the prior art employ a structure that one plunger  56  or one stopper pin, as a locking means, locks the rotor in the maximum timing retard position or in the maximum timing advance position, while the timings of the opening and closing of valves are adjusted at the starting of the engine.  
           [0034]    In general, for optimizing the timings of opening and closing of valves in an intake/exhaust system of an engine, for example, the engine shall be started from a state, in which the rotor in the intake side is shifted a little from the maximum timing retard position towards the maximum timing advance position, and the rotor in the exhaust side is shifted a little from the maximum timing advance position towards the maximum timing retard position. As a result, the rotors in the intake side and the exhaust side have to be locked at an intermediate position. However, the locking at an intermediate position was difficult, when the structures of the vane type hydraulic actuators in the prior art are employed. The apparatus will be of more complex, when such structure in the prior art is modified to lock the rotors in an intermediate position. That is to say, the vane type hydraulic actuator in the prior art has the drawback that an optimization of timings of opening and closing of valves using a simplified structure was impossible.  
         SUMMARY OF THE INVENTION  
         [0035]    An object of the present invention is to eliminate the drawback of the vane type hydraulic actuator in the prior art.  
           [0036]    Another object is to propose a vane type hydraulic actuator, in which the rotor can be locked securely at an arbitrary timing retard or timing advance position, when the engine is stopping, so that the timing of opening and closing of valves can be optimized.  
           [0037]    Another object is to propose a vane type hydraulic actuator, in which an unbalanced rotation of the rotor can be prevented.  
           [0038]    Another object is to propose a vane type hydraulic actuator, in which the assembling of the components for locking the rotor is easy.  
           [0039]    Another object is to propose a vane type hydraulic actuator, in which the rotor can be smoothly displaced to an arbitrary position, and the displaced rotor can be securely locked at the position.  
           [0040]    Another object is to propose a vane type hydraulic actuator, in which the relative velocity between the rotor and the case can be rapidly decreased, and simultaneously the allowance of dimensions of the components required in the assembling process can be loosened.  
           [0041]    Another object is to propose a vane type hydraulic actuator, in which the locking of the rotor can be released smoothly, using either of the oil pressure in the oil pressure chambers for timing retard or timing advance.  
           [0042]    Another object is to propose a vane type hydraulic actuator, in which the rotor can be held securely at any position where the locking of the rotor is released.  
           [0043]    Another object is to propose a vane type hydraulic actuator, in which the misassembling of components of the actuator in the production process can be absolutely prevented so that the efficiency of the assembling of components of the actuator can be improved.  
           [0044]    Another object is to propose a vane type hydraulic actuator, in which drawing back of locking elements from a rotor retaining position can be prevented.  
           [0045]    Another object is to propose a vane type hydraulic actuator, in which, when the rotor is offset from a locking position, the offset of rotor can be corrected, and the rotor can be securely locked at the corrected locking position.  
           [0046]    These objects are attained by a vane type hydraulic actuator according to the present invention, more specifically, a vane type hydraulic actuator comprising:  
           [0047]    a case having a plurality of shoes and being installed on the cam shaft of an engine so as to be rotatable independently therefrom;  
           [0048]    a rotor having a plurality of vanes and being received in the case, the rotor is fixed to the cam shaft of the engine and is rotatable relatively to the case in a predetermined angle region;  
           [0049]    an oil pressure chambers for timing retard and for timing advance disposed between the vanes of the rotor and the shoe of the case;  
           [0050]    and a locking means for retaining the rotor to the case so that the relative rotation between the case and the rotor is prevented;  
           [0051]    wherein the locking means comprises:  
           [0052]    a guide locking means for guiding the rotor to a predetermined locking position to lock the rotor to the case;  
           [0053]    and a retaining locking means for retaining the rotor to the case after that the rotor is guided to a predetermined locking position by the guide locking means.  
           [0054]    In an embodiment of the present invention, the guide locking means is disposed in a first vane, and the retaining locking means is disposed in a second vane located symmetrically with the first vane in respect with the axis of the rotor.  
           [0055]    In an embodiment of the present invention, the guide locking means and the retaining locking means are disposed in either of a vane of the rotor or a shoe of the case and are arranged to be adjacent to each other in the direction of the axis of the rotor, they are configured to move in the radial direction of the rotor so that the rotor can be locked to the case and can be disengaged from the case.  
           [0056]    In an embodiment of the present invention, the guide locking means has a first engaging boss formed as a tapered pin;  
           [0057]    the retaining locking means has a second engaging boss formed as a parallel pin;  
           [0058]    and the first and second bosses are received, respectively, in a first and second engaging recesses, each of which are formed so as to disengageably receive the bosses and are disposed in a portion rotating together with the case or alternately in the rotor.  
           [0059]    In an embodiment of the present invention, the guide locking means has a first engaging boss formed as a parallel pin; a first engaging recess is disposed in a portion rotating together with the case; and a friction increasing means is disposed in the base region of the first engaging recess so that the first engaging boss can contact with the friction increasing means.  
           [0060]    In an embodiment of the present invention, further comprising a lock releasing oil pressure channel for supplying oil pressure to the guide locking means and the retaining locking means so as to release the engagement between the rotor and the case; and an oil channel switching means for connecting the lock releasing oil pressure channel to either of the oil pressure chambers for timing retard or the oil chamber for timing advance.  
           [0061]    In an embodiment of the present invention, a fluid channel is disposed in a portion rotating together with the case so that spaces, which are formed behind each of the guide locking means and the retaining locking means when the rotor is locked to the case, communicate to the atmosphere through the fluid channel, only when the rotor is locked to the case.  
           [0062]    In an embodiment of the present invention, the cross section of the guide locking means is different from that of the retaining locking means.  
           [0063]    In an embodiment of the present invention, each of the guide locking means and the retaining locking means is urged so as to lock the rotor to the case by urging means; and the urging force of the urging means for the guide locking means is designed to be stronger than that of the urging means for the retaining locking means.  
           [0064]    In an embodiment of the present invention, the length in the peripheral direction of the tip portion of the vane having the guide locking means is substantially identical to that of the retaining locking means.  
           [0065]    In an embodiment of the present invention, the vane having the guide locking means and/or the vane having the retaining locking means have a weight balancing hole so as to balance the rotation of the rotor.  
           [0066]    In an embodiment of the present invention, the first engaging recess for receiving the guide locking means is tapered in such a manner that the tapering angle of the first engaging recess is larger than the tapering angle of the first engaging boss.  
           [0067]    In an embodiment of the present invention, the first engaging recess for receiving the first engaging boss of the guide locking means is disposed in a sliding means which is resiliently held in a portion rotating together with the case.  
           [0068]    According to the present invention, the locking means for retaining the rotor to the case is a combination of a guide locking means for guiding the rotor to a predetermined locking position and a retaining locking means for retaining the rotor to the rotor, which has been guided to the locking position. Therefore advantages are obtained in that, though the structure is simple, the rotor can be guided to a predetermined locking position using the guide locking means to lock it temporarily, and after temporarily locking, the rotor can be retained securely at an arbitrary position for a desired timing retard or for timing advance, using the retaining locking means, so that the timing of the opening and closing of the valves can be optimized.  
           [0069]    When the guide locking means is disposed in a first vane of the rotor, and the retaining locking means is disposed in a second vane symmetrical to the first vane in respect with the axis of the rotor, unbalanced rotation of the rotor can be prevented.  
           [0070]    When the guide locking means and the retaining locking means are designed to be disposed either in a common vane of the rotor or in a common shoe of the case, and they are arranged so as to be adjacent in the direction of the axis of the rotor, further they can move in the radial direction of the rotor, the efficiency of the production process is improved, because they can be assembled side by side. And the preciseness of the positioning of the rotor can be improved, because the rotor is temporarily locked by the guide locking means, which is found in the adjacent position of the retaining locking means.  
           [0071]    When the guide locking means has a first engaging boss formed as a tapered pin, and the retaining locking means has a second engaging pin formed as a parallel pin; and their corresponding engaging recess, having a recessed portion corresponding to those first and second engaging boss, are disposed in either of a portion rotating together with the case or the rotor so that they receive the first and second engaging boss, the tapered first engaging boss of the guide locking means can easily enter the corresponding tapered engaging recess. Therefore the rotor can be smoothly positioned to a predetermined locking position. And even when the position of the second engaging boss, formed as a parallel pin, of the retaining locking means is offset from the corresponding engaging recess, the offset can be corrected easily using the guide locking means. After correcting the position, the second engaging boss of the retaining means enters into the second engaging recess so that the rotor can be retained securely at an arbitrary position for timing retard and the timing advance, therefore the timing of opening and closing of the valves can be optimized.  
           [0072]    When the guide locking means has a first engaging boss formed as a parallel pin, and the first engaging recess for receiving loosely the first engaging boss is disposed in a portion rotating together with the case, further a friction increasing member is disposed in the base portion of the first engaging recess so that the first engaging boss can contact with it, the relative velocity between the rotor and the case decreases, due to the increased friction resistance between the first engaging boss and the first engaging recess. Thus, though the first engaging boss of the guide locking means is formed as a parallel pin, the retaining locking means can be easily and securely positioned to the retaining position of the rotor. And the retaining locking means can be securely driven to retain the rotor.  
           [0073]    When the vane type hydraulic actuator comprises a lock releasing oil channel for supplying oil pressure to the guide locking means and the retaining locking means so as to release the locking, and an oil channel switching means for switching the oil channel so that the lock releasing oil channel communicates with either of the oil chambers for timing retard or for timing advance, the oil channel from either of the oil chambers for timing retard or for timing advance can be supplied securely to both of the guide locking means and the retaining locking means so that they can be securely driven.  
           [0074]    When a fluid channel is disposed in a portion rotating together with the case so that spaces, which are formed behind the guide locking means and the retaining locking means when the rotor is locked, communicate with the atmosphere only when the rotor is locked, the guide locking means and the retaining locking means can be driven smoothly from a locking state to a locking releasing state.  
           [0075]    When the cross sectional area of the guide locking means is different from that of the retaining locking means, misassembling of guide locking means and the retaining locking means to an erroneous position in the production process can be prevented, so that the efficiency of the production can be ameliorated.  
           [0076]    When the urging force of the urging member for the guide locking means is designed to be stronger than that of the retaining locking means, once the first engaging boss of the guide locking means, formed as a tapered pin, engages with the first engaging recess for locking the rotor to the case, even when the rotation of rotor tends to disengage the first engaging boss from the first engaging recess, the first engaging boss does not disengage from the first engaging recess. Thus the rotor can be securely locked to a predetermined locking position. Additionally, the retaining locking means can be smoothly driven to release the locking, using small oil pressure, because the retaining locking means is urged by a small urging force.  
           [0077]    When the peripheral length of the tip portion of the vane having the guide locking means is designed to be substantially identical to that of the vane having the retaining locking means, the unbalancing of the rotor due to the installation of the guide locking means and the retaining locking means can be prevented.  
           [0078]    When a weight balancing hole is disposed in the first vane having the guide locking means and/or the second vane having the retaining locking means, the unbalanced rotation of the rotor due to the installation of the guide locking means and the retaining locking means can be prevented.  
           [0079]    When the tapering angle of the first engaging boss of the guide locking means is larger than that of the first engaging recess for receiving the first engaging boss, the first engaging boss can smoothly enter into the first engaging recess, therefore, even when the rotor is offset from the locking position, the offset can be easily and securely corrected.  
           [0080]    When the first engaging recess for loosely receiving the first engaging boss of the guide locking means is disposed in a slide means, which is resiliently held in a portion rotating together with the case, the first engaging boss of the guide locking means can easily enter into the first engaging recess so that the temporal positioning of the rotor using the guide locking means is easy. And the relative velocity between the rotor and the case decreases, due to the temporal positioning of the guide locking means. Therefore, the retaining locking means can be smoothly and securely driven to lock the rotor to the case. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0081]    [0081]FIG. 1 is a cross sectional view of a vane type hydraulic actuator according to first embodiment of the present invention.  
         [0082]    [0082]FIG. 2 is a cross sectional view of the vane type hydraulic actuator of FIG. 1, seen from the cover side, in which the cover and the housing are removed.  
         [0083]    [0083]FIG. 3 is a cross sectional view of the vane type hydraulic actuator of FIG. 1, seen from the housing side, in which the cover and the housing are removed.  
         [0084]    [0084]FIG. 4 is a detailed cross sectional view of the guide stopper pin receiving portion shown in FIG. 1.  
         [0085]    [0085]FIG. 5 is a cross sectional view of the retaining stopper pin, showing the movement when the oil pressure in the oil pressure chamber for timing advance is applied.  
         [0086]    [0086]FIG. 6 is a cross sectional view of the retaining stopper pin, showing the movement when the oil pressure in the oil pressure chamber for timing retard is applied.  
         [0087]    [0087]FIG. 7 is a cross sectional view of a main part of the vane type hydraulic actuator according to third embodiment of the present invention.  
         [0088]    [0088]FIG. 8 is a cross sectional view of the vane type hydraulic actuator of FIG. 7, seen from the cover side, when the cover is removed.  
         [0089]    [0089]FIG. 9 is a cross sectional view of the vane type hydraulic actuator of FIG. 7, seen from the housing side, when the housing is removed.  
         [0090]    [0090]FIG. 10 is a cross sectional view of a vane type hydraulic actuator according to fourth embodiment of the present invention.  
         [0091]    [0091]FIG. 11 is a cross sectional view of the main portion of the vane type hydraulic actuator according to the fifth embodiment of the present invention.  
         [0092]    [0092]FIG. 12 is a front view of the pin holder portion in FIG. 11.  
         [0093]    [0093]FIG. 13 is a cross-sectional view of the vane type hydraulic actuator according to the sixth embodiment of the present invention, showing along the axis of the rotor.  
         [0094]    [0094]FIG. 14 is a cross-sectional view of FIG. 13, showing along the line A-A in FIG. 13.  
         [0095]    [0095]FIG. 15 is a radial cross sectional view of the actuator, showing the oil channel switching system for driving the guide stopper pin and the retaining guide pin in FIGS. 13, 14.  
         [0096]    [0096]FIG. 16 is a cross sectional view of a vane type hydraulic actuator according to the seventh embodiment of the present invention.  
         [0097]    [0097]FIG. 17 is a cross sectional view of FIG. 16, showing along the line B-B.  
         [0098]    [0098]FIG. 18 is a cross sectional view of the vane type hydraulic actuator in the prior art.  
         [0099]    [0099]FIG. 19 is a detailed cross sectional view of the plunger portion in FIG. 18.  
         [0100]    [0100]FIG. 20 is a cross sectional view of the plunger portion at a state that an oil pressure is applied to the plunger.  
         [0101]    [0101]FIG. 21 is a cross sectional view of FIG. 18 along the line X-X.  
         [0102]    [0102]FIG. 22 is a partial sectional view of FIG. 21, at a state that the slide plate is displaced.  
         [0103]    [0103]FIG. 23 is a cross sectional view of FIG. 18 along the line Y-Y.  
         [0104]    [0104]FIG. 24 is a cross sectional view of FIG. 18 along the line Z-Z. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0105]    Embodiment 1:  
         [0106]    Embodiment 1 of the present invention is explained below, referring to FIGS.  1 - 6 . Components in these figures equivalent or corresponding to those in FIGS.  16 - 22  are referred to the same reference numerals, and their explanations are omitted.  
         [0107]    The rotor  44  is guided to a predetermined retaining position in respect with the case  43  by a guide stopper pin  1 , as a guide locking means, so that a phase angle between them is corrected. The guide stopper pin  1  has a first engaging boss  1   a  at its one end, which is formed as a tapered pin so that the diameter is decreasing towards the tip direction, and a spring receiving hole  1   b  at the opposite side of the guide stopper pin  1 . A first pin holding hole  2  is disposed in one vane  66  of four vanes of the rotor  44 , and is configured in the longitudinal direction of the rotor. The guide stopper pin  1  is received in the first pin holding hole  2  and can slide in the hole  2 .  
         [0108]    The housing  42 , which rotate together with the case  43 , has a first engaging recess  42   a  on the surface where the rotor  44  contacts and slide along it. The first engaging recess  42   a  is tapered so that the diameter increases in the direction towards the opening. The first engaging boss  1   a  of the guide stopper pin  1  can be disengageably received in the first engaging recess  42   a . The tapering angle θ2 of the first engaging recess  42   a  is designed to be larger than the tapering angle θ  1  of the first engaging boss  1   a  so that the first engaging boss  1   a  can easily enter into the first engaging recess  42   a.    
         [0109]    The guide stopper pin  1  is urged by a spring  3  towards the housing  42 . Namely the spring  3  functions as an urging means. When the first engaging boss  1   a  of the guide stopper pin  1  is pushed into the first engaging recess  42   a , due to the force of the first spring  3 , namely when they are engaged to each other, a first gap  2   a  is found between the housing  42  and the end surface of the guide stopper pin  1  where the first engaging boss  1   a  is disposed. The first gap  2   a  communicates with a first oil channel  58   a , which will be explained later, so that an oil pressure can be applied to the guide stopper pin  1  in the direction resisting the force of the spring  3 .  
         [0110]    Reference numeral  4  denotes a retaining stopper pin, which functions as a retaining locking means for retaining securely the rotor  44  to the case  43 , after that the phase angle between them is corrected by the guide stopper pin  1 . The retaining stopper pin  4  has a second engaging boss  4   a  formed as a parallel pin at a longitudinal end thereof, and a second spring holding hole  4   b  at the other end thereof. A second pin holding hole  5  is disposed in a vane of the rotor  44 , which is found at a symmetrical position of the vane  66 . The second pin holding hole  5  extends along the longitudinal direction of the rotor  44 , and the retaining stopper pin  4  is inserted therein so as to be able to slide in the longitudinal direction. That is to say, the guide stopper pin  1  and the retaining stopper pin  4  are disposed, respectively, in vanes  66 ,  64 , which are configured at a substantially symmetrical position on the rotor  44  in respect with the rotation axis of the rotor  44 . A second engaging recess  42   b  is disposed on a surface of the housing  42  where the rotor contacts and slide thereon. The second engaging hole  42   b  has a diameter which allow to insert the second engaging boss  4   a  of the retaining stopper pin  4  and to release the engagement of the second engaging boss  4   a  therefrom.  
         [0111]    The first engaging boss  1   a  of the guide stopper pin  1  and the first engaging recess  42   a  as well as the second engaging boss  4   a  of the retaining stopper pin  4  and the second engaging recess  42   b  are configured at, for example, a position shifted a little in the timing advance direction from the maximum timing retard position and a position shifted a little in the timing retard direction from the maximum timing advance position so that the vanes  64 - 67  of the rotor  44  can be locked at an arbitrary intermediate position apart from the shoes  71  of the case  43 .  
         [0112]    A second spring  6 , as an urging means, presses the retaining stopper pin  4  towards the housing  42 . The resilient force of the first spring  3  for the guide stopper pin  1  is designed stronger than that of the second spring  6 . When the second engaging boss  4   a  of the retaining stopper pin  4  is pushed into the second engaging recess  42   b , due to the force of the second spring  6 , namely when they are engaging to each other, a second gap  5   a  is found between the housing  42  and the end surface of the retaining stopper pin  4  where the second engaging boss  4   a  is disposed. The second gap  5   a  communicates with a second oil channel  58   b , which will be explained later, so that an oil pressure can be applied to the retaining stopper pin  4  in the direction resisting the force of the second spring  6 .  
         [0113]    The first and second pin holding holes  2 ,  5  communicate with the atmosphere, respectively, through drain channels  7 ,  8 , which functions simultaneously as an oil drain channel and as an air releasing hole.  
         [0114]    A first oil channel  58   a  is disposed in the vane  66  which has the guide stopper pin  1 . The first oil channel  58   a  connecting the groove  76  and the first gap  2   a  is comprised of a through-hole penetrating the vane  66  in parallel with the axis direction of the rotor. The groove  76  is disposed in the communicating channel  75 . The oil pressure chambers for timing retard and timing advance  73 ,  74  are connected through the groove  76 , as shown in FIG. 2. A slide plate  77  for opening and closing the first oil channel  58   a  is disposed in the groove  76  so as to function as a channel switching valve. When an oil pressure from the oil pressure chamber for timing retard is applied to the slide plate  77 , the slide plate  77  connects the first oil channel  58   a  to the oil pressure chamber for timing retard  73 , and cuts off the channel to the oil pressure chamber for timing advance  74 . On the other hand, when an oil pressure from the oil pressure chamber for timing advance  74  is applied to the slide plate  77 , the slide plate  77  connects the first oil channel  58   a  to the oil pressure chamber for timing advance  74  and cuts off the oil channel to the oil pressure chamber for timing retard  73 .  
         [0115]    The first gap  2   a , the first oil channel  58 , the communicating channel  75  and the groove  76  form an oil channel for releasing the locking of the guide stopper pin  1 , by delivering oil pressure to release the locking of the guide stopper pin  1 . And the slide plate  77  forms an oil channel switching means for connecting the oil channel for releasing the lock of the guide stopper pin to either of the oil pressure chambers for timing retard and timing advance.  
         [0116]    A second oil channel  58   b  is disposed in the vane  64 , which is found at a symmetrical position to the vane  66  having the first oil channel  58 . The vane  64  has a retaining stopper pin  4 . The second oil channel  58   b  is comprised of a through-hole penetrating the vane  64 , and the groove  76  and the second gap  5   a  is connected through the second oil channel  58   b.    
         [0117]    Also in this oil pressure system for the retaining stopper pin  4 , similar to the oil pressure system for the guide stopper pin  1 , the second gap  5   a , second oil channel  58   b , communicating channel  75  and the groove  76  form a lock releasing oil pressure channel for supplying oil pressure to the retaining stopper pin  4  in the direction to release the locking of the retaining stopper pin  4 . And the slide plate  77  functions as an oil channel switching means for connecting the lock releasing oil channel either to the oil pressure chamber for timing retard  73  or to the oil pressure chamber for timing advance  74 .  
         [0118]    In FIG. 2, the length L 1  is the peripheral width of the tip portion of the vane  64  having the retaining stopper pin  4 . The length L 2  is the peripheral width of the tip portion of the vane  66  having the guide stopper pin  1 . The lengths L 1  and L 2  are designed to be substantially equal.  
         [0119]    The function of the first embodiment is explained below.  
         [0120]    When first and second bosses  1   a ,  4   a  of the guide stopper pin  1  and the retaining stopper pin  4  are inserted respectively in the first and second engaging recesses  42   a ,  42   b , so that the case  43  incorporated in the housing  42  is engaging with the rotor  44  so as to rotate together with, as shown in FIG. 1, oil pressure is supplied to the guide stopper pin  1  and the retaining stopper pin  4  from the oil pressure chambers for timing retard  73  or timing advance  74  through the first or second gaps  2   a ,  5   a . When the oil pressure exceeds the resilient force of the springs  3 ,  6 , the first and second bosses  1   a ,  4   a  of the guide stopper pin  1  and the retaining stopper pin  4  pushed out from the first and second engaging recesses  42   a ,  42   b . As a result the locking between the case  43  and the rotor  44  is released, so that they can rotate independently. While the locking is released, the relative position between the case  43  and the rotor  44  can be adjusted so as to optimize the timing of opening and closing of the valves.  
         [0121]    Starting from this lock released state, when the oil pressure supplied to the guide stopper pin  1  and the retaining stopper pin  4  is decreased to be lower than the resilient force of the springs  3 ,  6 , the guide stopper pin  1  and the retaining stopper pin  4  displace, respectively, to enter into the first and second engaging recesses  42   a ,  42   b . However, there may be a case that the position of the case  43  and the position of the rotor  44 , are offset from a regular engaging position, where the second engaging boss  4   a  can enter into the second engaging recess  42   b . Namely there is a case that they are not aligned exactly to each other. Even in such a case, the offset can be corrected and the first engaging boss  1   a  can enter smoothly into the first engaging recess  42   a , because the first engaging boss  1   a  of the guide stopper pin  1  and the corresponding first engaging recess  42   a  are tapered, more specifically, the tapering angle θ2 of the engaging recess  42   a  is designed smaller than the tapering angle θ1 of the engaging boss  1   a . When the offset of the position of the rotor is corrected, the second engaging boss  4   a  of the retaining stopper pin  4  aligns to the second engaging recess  42   b , then, the retaining stopper pin  4  advances due to the resilient force of the spring  6  so that the engaging boss  4   a  enters into the engaging recess  42   b . As a result, the rotor  44  is locked to the case  43 , and they can rotate synchronously. To sum up, even when the relative position of the case  43  and the rotor  44  is offset from a regular engaging position, the offset can be corrected by the guide stopper pin  1 , and the rotor  44  can be locked securely by the retaining stopper pin  4  to the case  43  at the corrected position.  
         [0122]    While the position of the rotor  44  is adjusted either to the direction of the timing retard or the timing advance, the slide plated  77  takes either of the two positions, a position in which the first oil channel  58   a  and the second oil channel  58   b  are connected to the oil pressure chamber for timing advance  74 , as shown in FIG. 5 (only the second oil channel  58   b  is shown), or a position in which the first oil channel  58   a  and the second oil channel  58   b  are connected to the oil pressure chamber for timing retard  73 , as shown in FIG. 6 (only the second oil channel  58   b  is shown). Therefore, while the position of the rotor  44  is adjusted either to the direction of the timing retard or the timing advance, oil pressure can be applied securely to both of the guide stopper pin  1  and the retaining stopper pin  4  either from the oil pressure chambers for the timing advance  74  or the timing retard  73  so that the both the guide stopper pin  1  and the retaining stopper pin  4  can be displaced smoothly in the lock releasing direction due to oil pressure. The other functions of this vane type hydraulic actuator according to the first embodiment of the present invention are substantially identical to that of the prior art, thus their explanations are omitted.  
         [0123]    According to the first embodiment, advantages can be obtained in that, although the structure of the vane type hydraulic actuator is simple, the rotor  44  can be securely retained at a position for timing retard or at a position for timing advance while the engine is stopping so that the timing of opening and closing of the valves can be optimized. Because, after the rotor  44  is guided to a regular engaging position, where the second engaging boss  4   a  of the retaining stopper pin  4  aligns to the second engaging recess  42   b , the second engaging boss  4   a , formed as a parallel pin, of the retaining stopper pin  4  is pushed into the second engaging pin  42   b  by the resilient force of the spring  6  so that the rotor  44  engages with the case  2  at the position.  
         [0124]    Another advantage is that the engaging position between the first engaging boss  1   a  of the guide stopper pin  1  and the first engaging recess  42   a  and the engaging position between the second engaging boss  4   a  of the retaining stopper pin  4  and the second engaging recess  42   b  can be so designed that the vanes  64 - 67  of the rotor  44  lock the rotor  44  and the case  43  at an intermediate position apart from the shoes  71  of the case  43 , thus, the rotor  44  can be locked securely at an arbitrary timing retard position or at an arbitrary timing advance position. As a result, the timing of the opening and closing timing of the valves can further optimized.  
         [0125]    Another advantage is that the first engaging boss  1   a  can enter smoothly into the first engaging recess  42   a , even when the position of the rotor  44  relative to the case  43  is offset from the regular locking position. Because the tapering angle θ2 of the second engaging recess  42   a  is larger than the tapering angle θ1 of the first engaging boss  1   a  of the guide stopper pin  1 . The difference between the angles θ1 and θ2 is an allowance for the engagement of the rotor  44  and the case  43 . Within the allowance, the position of the rotor  44  can be corrected to the regular engaging position, and the rotor  44  can be locked securely by means of the retaining stopper pin  4 .  
         [0126]    Another advantage is that an unbalanced rotation of the rotor  44  can be avoided. Because the vane  66  having the guide stopper pin  1  and the vane  64  having the retaining stopper pin  4  are disposed symmetrically in respect with the axis of the rotor  44 , and the lengths L 1 , L 2  of their tip portions in the peripheral direction are substantially equal.  
         [0127]    Another advantage is that, once the first engaging boss  1   a  of the guide stopper pin  1  enters into the first engaging recess  42   a , disengagement of the first engaging boss  1   a  and the first engaging recess  42   a  due the rotation of the rotor  44  can not occur. Because the resilient force of the spring  3  urging the guide stopper pin  1  is stronger than the resilient force of the spring  3  urging the retaining stopper pin  4 . If the resilient force for the guide stopper pin  1  having a tapered engaging boss  1   a  is weak, there is an apprehension that the tapered engaging boss  1   a  will disengage from the first engaging recess  42   a . In this embodiment, such an apprehension is removed, and the resilient force of the spring  3  for the retaining stopper pin  4  can be designed to be weak.  
         [0128]    Embodiment 2:  
         [0129]    In the first embodiment, the peripheral lengths L 1 , L 2  of the tip portion of the vane  66  having the guide stopper pin  1  and the tip portion of the vane  64  having the retaining stopper pin  4  are designed to be substantially equal, from a view point of the rotation balance of the rotor  44 . In the second embodiment, a weight balancing recess (not shown) is disposed in either of the vanes  66 ,  64 , for maintaining the rotation balance of the rotor  44 . The other structure, function, and advantage are identical to those of the first embodiment.  
         [0130]    Embodiment 3:  
         [0131]    A vane type hydraulic actuator according to the third embodiment of the present invention is explained below, referring to FIGS.  7  to  9 .  
         [0132]    Reference numeral  48   a  in FIG. 7 denotes a fluid channel disposed on the contacting surface of the cover  48 , which rotates together with the case  43 . The rotor  44  contacts with this contacting surface and slides along it. Only when the retaining second stopper pin  4  is engaging with the second engaging recess  42   b  and the rotor  44  is retained, a fluid channel  8  behind the rotor  44  communicates with the fluid channel  48   a  so that the space behind the rotor  4  including the second pin holding hole  5  is opened to the atmosphere.  
         [0133]    When the second engaging boss  4   a  of the retaining stopper pin  4  is disengaged from the second engaging recess  42   b  and the retaining of the rotor  44  is released, the cover  48  integrating case  43  rotates relatively to the rotor  44 , therefore the position of the fluid channel  48  in the cover  48  is offset from the fluid channel  8  in the rotor  44 , as a result, the fluid channel  8  in the rotor  44  is cut off by the cover  48 .  
         [0134]    In addition to the fluid channel  48   a , another fluid channel (not shown) is disposed in the cover  48 , which is connected to a similar fluid channel  7  for the system of the guide stopper pin  1 . The structure and the function of the fluid channel is identical to the fluid channel  48   a , thus their explanations are omitted.  
         [0135]    In this embodiment, the cross sectional area of the guide stopper pin  1  is not always equal to that of the retaining stopper pin  4 . For example, the cross sectional area of the guide stopper pin  1 , shown in FIG. 9, is smaller compared to that of the retaining stopper pin  4 . Otherwise, the cross sectional area of the guide stopper pin  1  can be larger than that of the retaining stopper pin  4 .  
         [0136]    The other features of the third embodiment of the present invention are identical to those of the first embodiment. Thus the components equivalent or corresponding to those in the first embodiment are referred to the same reference numerals, and their explanations are omitted.  
         [0137]    According to the third embodiment, advantages can be obtained in that the retaining stopper pin  4  and the guide stopper pin  1  can be smoothly displaced from a position retaining the rotor  44  to a retaining releasing position. Because a fluid channel  48   a  for the system of the retaining stopper pin  4  and a fluid channel (not shown) for the system of the guide stopper pin  1  are disposed on the contacting surface of the cover  48 , where the rotor  44  contacts and slides along it, so that, only when the rotor  44  is locked, the fluid channels can, respectively, communicate with the fluid channel  8  in the system for the retaining stopper pin  4  and the fluid channel (not shown) in the system for the guide stopper pin  1 .  
         [0138]    Another advantage is that miss-assembling of the guide stopper pin  1  and the retaining stopper pin  4  in the fabrication process can be avoided, when the cross-sectional area of the guide stopper pin  1  and that of the retaining stopper pin  4  are different. For example, miss-assembling of the retaining stopper pin  4 , instead of the guide stopper pin  1 , into the first pin holding hole  2  corresponding to tapered first engaging recess  42   a  can be prevented. As a result, the efficiency of the assembling of the components of the apparatus can be improved.  
         [0139]    Embodiment 4:  
         [0140]    Fourth embodiment of the present invention is explained below, referring to FIG. 10.  
         [0141]    Reference numeral  1   c  in FIG. 10 denotes a first engaging boss disposed at an end in the longitudinal direction of the guide stopper pin  1 . The first engaging boss  1   c  is formed as a parallel pin. The first engaging boss  1   c  engages into a first engaging recess  42   c  disposed on the contacting surface of the housing  42  having a diameter larger than that of the first engaging boss  1   c . The rotor  44  contacts with this contacting surface and slides on it. When the first engaging boss  1   c  enters into the first engaging recess  42   c , the first engaging boss  1   c  contacts with a friction increasing member  9  disposed in the base region of the first engaging recess  42   c . That is to say, in the fourth embodiment, the first engaging boss disposed at an end of the guide stopper pin  1  is formed as a parallel pin; the diameter of the first engaging recess  42   c , into which the first engaging boss  1  enters, is larger than that of the first engaging boss  1   c ; a friction increasing member  9  is disposed in the base region of the first engaging recess  42   c ; and the tip portion of the first engaging boss  1   c  contacts with the friction increasing member  9 . The other features of the fourth embodiment is identical to those of the first embodiment of the present invention. Thus components identical or equivalent to those in the first embodiment are referred to the same reference numeral, and their explanation is omitted.  
         [0142]    The function of the vane type hydraulic actuator according to the fourth embodiment is explained below.  
         [0143]    When the guide stopper pin  1  is urged by the resilient force of the spring  3  so that the first engaging boss  1   c  enters into the first engaging recess  42   c , and the tip of the first engaging boss  1   c  contacts with the friction increasing member  9 , the relative velocity between the rotor  4  and the housing  42  decreases corresponding to the increased friction resistance of the first engaging boss  1   c . As a result, the movement of the retaining stopper pin  4  to lock the rotor  4  is rendered smooth.  
         [0144]    The features of the fourth embodiment is found in that the first engaging boss  1   c  of the guide stopper pin  1  is formed as a parallel pin; the diameter of the first engaging recess  42   c  is larger than the diameter of the first engaging boss  1   c , which enters into the first engaging recess  42   c ; a friction increasing member  9  is disposed in the base portion of the first engaging recess  42   c ; and the first engaging boss  1   c  contacts with the friction increasing member  9 . Once the first engaging boss  1   c  of the guide stopper pin  1  contacts with the friction increasing member  9  for locking the rotor  44 , the relative velocity between the rotor  4  and the housing  42  decreases due to the increased friction resistance.  
         [0145]    Consequently, according to these features of the fourth embodiment of the present invention, advantages can be obtained in that, though the first engaging boss  1   c  of the guide stopper pin  1  is formed as a parallel pin, the positioning of the rotor  44  to the locking position by means of the retaining stopper pin  4  is easy, and the retaining stopper pin  4  can move smoothly and securely in the engaging direction to lock the rotation of the rotor  44 .  
         [0146]    Embodiment 5:  
         [0147]    The vane type hydraulic actuator according the fifth embodiment of the present invention is explained below, referring to FIGS. 11 and 12.  
         [0148]    A pin holder  11  is installed in a recessed groove  10  disposed on the contacting surface of the housing  42 , which rotates together with the case  43 . The rotor  44  contacts with the contacting surface and slides along it. The pin holder  11  has a second engaging recess portion  42   d , which is tapered so that the engaging boss  1   a  of the guide stopper pin  1  can enter in it and disengage from it. The pin holder  11  can slide in the recessed groove  10 .  
         [0149]    A pair of balance springs  12 A,  12 B are disposed in the recessed groove  10  at both sides of the pin holder  11 . The balance springs functions as a resilient holding means for holding the pin holder  11  so that the pin holder  11  can move in the radial direction of the rotor  44 . The recessed groove  10  is covered by a cover  13 , which has an opening  13   a  communicating with the second engaging recess portion  42   d . The diameter of the opening  13   a  is larger than the diameter of the second engaging recess portion  42   d  at the larger diameter side. The inner surface of the cover  13  is coplanar with the inner surface of the housing  42  (the contacting surface of the rotor  44 ). Otherwise, the pair of the balance springs  12 A,  12 B can be arranged so that the pin holder  11  can move in the rotation direction of the rotor  44 . The other structure and function of the fifth embodiment are identical to those of the first embodiment.  
         [0150]    The function of the fifth embodiment is explained below.  
         [0151]    When the rotor  44  is locked, the guide stopper pin  1  is pushed by the resilient spring  3  so that the first engaging boss  1   a  of the guide stopper pin  1  enters into the first engaging recess  42   d  through the opening  13   a  and the guide stopper pin  1  is temporarily locked to the housing  42 , in a similar way as in the first embodiment.  
         [0152]    Even when the first engaging boss  1   a  of the guide stopper pin  1  is not positioned just in front of the first engaging recess  42   d  in the pin holder  11  and they are not aligned to each other, the first engaging boss  1   a  can enter easily into the first engaging recess  42   d  and can be held at a center portion of the balance springs  12 A,  12 B, that is an equilibrium position of the resilient force of the balance springs. After the temporal locking, the relative velocity between the rotor  44  and the housing  42  decreases so that the retaining stopper pin  4  can move smoothly and securely in the direction to lock the rotor  44 .  
         [0153]    As explained above, the features of the fifth embodiment are such that the first engaging boss  1   a  of the guide stopper pin  1  is tapered; a pin holder  11  having a tapered engaging recess  42   d , in which the first engaging boss  1   a  can engage, is installed in a groove  10  disposed in the housing  42 ; the pin holder  11  is resiliently held by a pair of balance springs  12 A,  12 B. Thus, the first engaging boss  1   a  of the guide stopper pin  1  can easily enter into the first engaging recess  42   d  in the pin holder  11  so that the rotor  44  can be smoothly locked temporarily, and the relative velocity between the rotor  44  and the housing  42  decreases because of the temporal locking of the rotor  44 . Consequently, advantages can be obtained in that the retaining stopper pin  4  can be displaced smoothly and securely in the direction to lock the rotor  44 , and that a large allowance in assembling of the pin holder  11  into the housing  42  is permissible, because the pin holder  11  is held by a pair of balance springs  12 A,  12 B.  
         [0154]    Embodiment 6:  
         [0155]    The vane type hydraulic actuator according to the sixth embodiment is explained, referring to FIGS.  13  to  16 . Components identical or corresponding to those explained referring to FIGS.  1 - 9  are referred to the same reference numerals, and their explanations are omitted.  
         [0156]    A first pin holding hole  102  and a second pin holding hole  105  penetrate a shoe  71  of the case  43  in the radial direction. The first and second holding holes  102 ,  105  are arranged side by side in the direction of the axis of the rotor  44 . There is a shoulder portion in each of the first and second pin holding holes  102 ,  105 , more specifically, the inner diameter of each of the first and second pin holding holes  102 ,  105  is small at the radially inner portion.  
         [0157]    The first pin holding hole  102  receives a guide stopper pin  101 , which can slide in the radial direction in the hole  102 . The guide stopper pin has a first engaging boss  101   a  formed as a tapered pin at its radially inner end portion and a spring holding hole  101   b  which has an opening at its radially outer end. The guide stopper pin  101  functions as a guide locking means for securely guiding the rotor  44  to a predetermined position to engage with the housing. The guide stopper pin  101  is pushed towards the rotor  44  by a first spring  103 . The first spring  103  is held by a plug  102   a , which is plugged into the radially outer opening of the first pin holding hole  102 .  
         [0158]    A first engaging recess  142   a  is disposed in the hub portion of the rotor  44 , which contacts with the shoe  71 , having the first pin holding hole  102 , and slides along it. The first engaging recess  142   a  is tapered so that the inner diameter increases gradually outwardly. Thus the first engaging boss  101   a  of the guide stopper pin  101  can enter into the first engaging recess  142   a  and exit from there. When the first engaging boss  101   a  enters in it, the position of the rotor  44  in respect with the case  43  can be corrected, the correction facilitates the engagement of the retaining locking means, as will be explained below.  
         [0159]    The second pin holding hole  105 A receives a retaining stopper pin  104 , which can slide in the radial direction of the case  43 . The retaining stopper pin has a second engaging boss  104   a , formed as a parallel pin with small diameter, in its radially inner portion, and a second spring holding hole  104   b , which has an opening at its radially outer end portion. The retaining stopper pin  104  functions as a retaining locking means for retaining securely the rotor  44  at a predetermined position. The retaining stopper pin  104  is pushed towards the rotor  44  by a second spring  106 . The outer opening of the second spring holding hole  104   b  is plugged by a plug  105   a , which holds the second spring  106 .  
         [0160]    A second engaging recess  142   b  is disposed in the hub portion of the rotor  44 , with which the shoe  71  having the retaining stopper pin  104  contacts. The second engaging recess  142   b  is arranged adjacently to the first engaging recess  142   a , which belongs to the system for the guide stopper pin  101 , and is formed as a cylindrical hole matched with the second engaging boss  104   a  so that the second engaging boss  104   a  of the retaining stopper pin  104  can enter and exit from it. Preferably, the resilient force of the first spring  103  for the guide stopper pin  101  is designed to be stronger than that of the second spring  106  for the retaining stopper pin  104 .  
         [0161]    In the first and second embodiments, each of the vane  66  having the guide stopper pin  1  and the vane  64  having the retaining stopper pin  4  has an oil channel for releasing the locking (oil channel  58   a ,  58   b , communicating oil channel  75 , and groove), and an oil channel switching means (slide plate  77 ). On the other hand, in the sixth embodiment, the guide stopper pin  101  and the retaining stopper pin  104  have a common lock releasing oil pressure channel (oil channel  58   a , communicating channel  75 , and groove  76 ) and an oil channel switching means (slide plate  77 ) on a shoe  71  projecting towards the rotor shaft. And the guide stopper pin  101  and the retaining stopper pin  104  are simultaneously activated. The function of these lock releasing oil pressure channel and the oil channel switching means are substantially identical to those in the first embodiment. Thus their explanation is omitted.  
         [0162]    By the way, the oil channel  58   a  of the lock releasing oil channel supplies oil pressure, which is delivered either from the oil chambers for timing retard  73  and the for timing advance  74 , to the guide stopper pin  101  and the retaining stopper pin  104 . The oil pressure urges the guide stopper pin  101  and the retaining stopper pin  104  in the direction resisting the resilient force of the first and second springs  103 ,  106 . Of course, also in the sixth embodiment, it is possible to dispose two sets of the lock releasing oil pressure channel and the oil switching means for independently activating the guide stopper pin  101  and the retaining stopper pin  104 . In such a structure, it is preferable to arrange a set of the lock releasing oil pressure channel and the oil switching means on each inner and outer end surfaces of the shoe  71 .  
         [0163]    The function of the vane type hydraulic actuator according to the sixth embodiment of the present invention is explained below.  
         [0164]    When the engine is running, the case  43  and the rotor  44  have to rotate independently to each other. In this state, the oil pressure urging the guide stopper pin  101  and the retaining stopper pin  104  is set larger than the resilient force of the first and second spring  103 ,  106 , so that the first and second engaging boss  101   a ,  104   a  of the guide stopper pin  101  and the retaining stopper pin  104  are pushed out from the first and second engaging recesses  142   a ,  142   b . As a result, the locking of the rotor is released in this state.  
         [0165]    Starting from this locking released state, when the oil pressure urging the guide stopper pin  101  and the retaining stopper pin  104  decreases to be lower than the resilient force of the first and second springs  103  and  106 , if, in this moment, the first engaging boss  101   a  of the guide stopper pin  101  and the second engaging boss  104   a  of the retaining stopper pin  104  are positioned exactly aligned to the corresponding first and second engaging recesses  142   a ,  142   b  the first and second engaging bosses  101   a ,  104   a  of the guide stopper pin  101  and the retaining stopper pin  104  will enter into the first and second engaging recess  142   a ,  142   b  due the resilient force of the first and second spring  103 ,  106 , so that the case  43  and the rotor  44  are locked to each other.  
         [0166]    However, when the oil pressure urging the guide stopper pin  101  and the retaining stopper pin  104  decreased to be lower than the resilient force of the first and second springs  103 ,  106 , the first engaging boss  101   a  of the guide stopper pin  101  and the second engaging boss  104   a  of the retaining stopper pin  104  are not always positioned exactly aligned to the corresponding first and second engaging recesses  142   a ,  142   b , namely they can be offset a little from a regular engaging position.  
         [0167]    When the offset is within the difference between the diameter of the smaller diameter side tip portion of the first engaging boss  101   a  of the guide stopper pin  101 , which is formed as a tapered pin, and the diameter of the opening of the tapered first engaging recess  142   a  at the largest end, the first engaging boss  101   a  can be pushed into the first engaging recess  142   a  by the resilient force of the first spring  103  urging the guide stopper pin  101 . As a result, the offset can be corrected. And the second engaging boss  104   a , which is formed as a cylindrical pin, of the retaining stopper pin  104  and the cylindrically formed second engaging recess  142   b  align to each other, then the cylindrically formed second engaging boss  104   a  enters into the cylindrically formed second engaging recess  142   b , due to the resilient force of the second spring  106  urging the retaining stopper pin  104 . Finally, the rotor  44  can be locked to the case  43 .  
         [0168]    The resilient force of the first spring  103  of the guide stopper pin  104  can be designed to be larger than that of the retaining stopper pin  104 . In such a case, when the oil pressure, which urges commonly the guide stopper pin  101  and the retaining stopper pin  104 , is decreased to be lower than the resilient force of the first and second springs  103 ,  106 , even when the first and second engaging bosses  101   a ,  104   a  and the first and second engaging recesses  142   a ,  142   b  are not aligned, the first engaging boss  101   a  of the guide stopper pin  101  enters into the first engaging recess  142   a , because the resilient force of the first spring  103  of the guide stopper pin  101  is larger than that of the second spring  106  of the retaining stopper pin  104 . Then the second engaging boss  104   a  of the retaining stopper pin  104  and the second engaging recess  142   b  align to each other, and the second engaging boss  104   a  can smoothly enter into the second engaging recess  142   a.    
         [0169]    According to the sixth embodiment of the present invention, advantages can be obtained in that the efficiency of the assembling in the production process of the vane type hydraulic actuator is improved, because the guide stopper pin  101  and the retaining stopper pin  104  are disposed on the shoe  71  so as to be adjacent to each other in the direction of the axis of the rotor  44 . And even when the position of the second engaging boss  104   a  of the retaining stopper pin  104  is offset form the position of the second engaging recess  142   b , the first engaging boss  101   a  of the guide stopper pin  101  can enter smoothly into the first engaging recess  142   a , because the first engaging boss  101   a  of the guide stopper pin is tapered and the first engaging recess  142   a  is tapered so as to allow to receive the first engaging boss  101   a , so that the offset of the position of the second engaging boss can be corrected when the first engaging boss  101   a  enters into the first engaging recess  142   a . As a result, the second engaging boss  104   a  of the retaining stopper pin  104  can enter smoothly into the second engaging recess  142   b , Consequently, the rotor  44  can be locked securely at a predetermined position. Furthermore, the preciseness of the correction of the offset can be improved, because the offset of the retaining stopper pin  104  is corrected by the guide stopper pin  101  disposed at a position very close to the retaining stopper pin  104 .  
         [0170]    In the aforementioned example of the sixth embodiment, the guide stopper pin  101  and the retaining stopper pin  104  are disposed on a shoe  71  of the case  43  so as to be arranged side by side in the direction of the axis of the rotor, and is possible to slide in the radial direction of the rotor. However, they can be disposed in one of the vanes  64 - 67  of the rotor  44  so as to be arranged side by side in the direction of the axis of the rotor  44  and be possible to slide in the radial direction. In such a case, similar advantages such as obtained in the explained example of the sixth embodiment can be obtained, by disposing the first and second engaging recesses  142   a ,  142   b  on the inner surface of the case  43 , where the vane having the guide stopper pin  101  and the retaining stopper pin  104  contact and slide along it.  
         [0171]    Furthermore, also in the sixth embodiment, the guide stopper pin  101  as well as the first engaging recess  142   a  and that of the retaining stopper pin  104  as well as the second engaging recess  142   b  can have different cross sectional areas. The advantages derived from such a structure are identical to that of the third embodiment.  
         [0172]    Embodiment 7:  
         [0173]    The vane type hydraulic actuator according to the seventh embodiment of the present invention is explained below, referring to FIGS. 16, 17. Components in FIGS. 16, 17 identical or equivalent to those in FIGS.  1  to  9  and  13  to  15  are referred to the same reference numerals, and their explanations are omitted.  
         [0174]    In the sixth embodiment, the guide stopper pin  101  and the retaining stopper pin  104  are disposed in a common shoe  71  of case  43  so as to be adjacent in the direction of the rotor  44 . On the other hand, in the seventh embodiment, the guide stopper pin  101  (guide locking means) and the retaining stopper pin  104  (retaining locking means) are disposed on different shoes  71 , which are located symmetrically in respect with the axis of the rotor  44 . The guide stopper pin  101  and the retaining stopper pin  104  are configured symmetrically in respect with the axis of the rotor  44  and can slide in the radial direction of the rotor  44 .  
         [0175]    The first engaging recess  142   a  for disengageably receiving the first engaging boss  101   a  of the guide stopper pin  101  and the second engaging recess  142   b  for disengageably receiving the second engaging boss  104   a  of the retaining stopper pin  104  are disposed in the hub portion of the rotor  44  symmetrically in respect with the axis of the rotor  44 .  
         [0176]    The functions of the guide stopper pin  101  and the retaining stopper pin  104  are similar to those of the sixth embodiment, thus, their explanation is omitted.  
         [0177]    According to the seventh embodiment, advantages can be obtained in that the longitudinal length of the hydraulic actuator can be shortened compared to that of the sixth embodiment, in which the guide stopper pin  101  and the retaining stopper pin  104  are disposed adjacent in the direction of the rotor axis. Because, in the seventh embodiment, the guide stopper pin  101  and the retaining stopper pin  104  are disposed symmetrically in respect with the rotor axis, and the first engaging recess  142   a  for disengageably receiving the first engaging boss  101   a  of the guide stopper pin  101  and the second engaging recess  142   b  for disengageably receiving the second engaging boss  104   a  of the retaining stopper pin  104  are disposed in the hub portion of the rotor  44  symmetrically in respect with the axis of the rotor  44 . As a result, the hydraulic actuator  40  can be downsized. Further, the weight of the hydraulic actuator  40  can be balanced, because the guide stopper pin  101  and the retaining stopper pin  104  are disposed symmetrically in respect with the rotor axis, as explained above, therefore the rotation of the actuator  40  can be stabilized.