Patent Publication Number: US-2021172346-A1

Title: Valve opening and closing timing control device

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and claims priority under 35 U.S.C. § 119 to Japanese Patent Application 2019-221341, filed on Dec. 6, 2019, the entire content of which is incorporated herein by reference. 
     TECHNICAL FIELD 
     This disclosure relates to a valve opening and closing timing control device that controls opening and closing timing of a valve. 
     BACKGROUND DISCUSSION 
     A valve opening and closing timing control device includes a drive-side rotary body that rotates synchronously with a crankshaft of an internal combustion engine, and a driven-side rotary body that is arranged coaxially with a rotation axis of the drive-side rotary body and rotates integrally with a camshaft for opening and closing a valve. By supplying fluid to and discharging fluid from an advance chamber and a retard chamber formed between the drive-side rotary body and the driven-side rotary body, a relative rotation phase between the drive-side rotary body and the driven-side rotary body is controlled. It is known that the valve opening and closing timing control device includes a valve unit that controls the supply of the fluid to and discharge of the fluid from the advance chamber and the retard chamber, and a coupling bolt that houses the valve unit in an internal space in a direction along the rotation axis (for example, see JP-A-2018-91226 (Reference 1)). 
     In the valve opening and closing timing control device described in Reference 1, as the valve unit, a sleeve, a spool movable in the rotation axis direction, and a fluid supply pipe are arranged in order from an outer side to an inner side in a radial direction in the internal space of the coupling bolt. Further, the valve opening and closing timing control device includes a lock mechanism that can switch between a lock state in which the valve opening and closing timing control device is restrained to an intermediate phase between a most retarded phase and a most advanced phase and a lock release state in which the restraint of the intermediate phase is released. 
     Reference 1 discloses an embodiment in which, in the lock state, a lock drain flow path through which the fluid is discharged from the lock mechanism extends in the rotation axis direction of the coupling bolt, and an advance chamber drain flow path through which the fluid is discharged from the advance chamber extends in the rotation axis direction of the coupling bolt as a flow path different from the lock drain flow path. The lock drain flow path also serves as a retard chamber drain flow path through which the fluid is discharged from the retard chamber. That is, the advance chamber drain flow path and the retard chamber drain flow path extending in the rotation axis direction are arranged at different positions in a circumferential direction on the coupling bolt. 
     In the valve opening and closing timing control device described in Reference 1, a plurality of drain flow paths in the rotation axis direction are extended to the coupling bolt. Accordingly, a flow path cross-sectional area of the advance chamber drain flow path and the retard chamber drain flow path for phase control is limited. As a result, at the time of the phase control, a speed at which the fluid is discharged from the advance chamber or the retard chamber may be reduced, and responsiveness of the phase control may be deteriorated. 
     A need thus exists for a valve opening and closing timing control device which is not susceptible to the drawback mentioned above. 
     SUMMARY 
     A characteristic configuration of a valve opening and closing timing control device according to an aspect of this disclosure resides in that the valve opening and closing timing control device includes a drive-side rotary body that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotary body that is provided inside the drive-side rotary body in a state of being coaxial with a rotation axis of the drive-side rotary body and that rotates integrally with a camshaft for opening and closing a valve; an advance chamber and a retard chamber formed between the drive-side rotary body and the driven-side rotary body; a valve unit that includes a spool movable in a rotation axis direction and that controls supply and discharge of fluid to and from the advance chamber and the retard chamber; a tubular valve case that has an internal space extending along the rotation axis inside the driven-side rotary body in a radial direction and that houses the valve unit in the internal space; a first drain flow path through which the fluid is discharged from any one of the advance chamber or the retard chamber through the spool; and a second drain flow path through which the fluid is discharged from the other one of the advance chamber or the retard chamber through the spool, in which the first drain flow path and the second drain flow path extend in directions intersecting each other at different positions in the rotation axis direction. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The foregoing and additional features and characteristics of this disclosure will become more apparent from the following detailed description considered with the reference to the accompanying drawings, wherein: 
         FIG. 1  is a cross-sectional view showing a valve opening and closing timing control device; 
         FIG. 2  is a cross-sectional view taken along a line II-II of  FIG. 1 ; 
         FIG. 3  is a diagram listing a relationship between a position of a spool and supply and discharge of working oil; 
         FIG. 4  is a cross-sectional view of a valve unit in which the spool is in a first advance position; 
         FIG. 5  is a cross-sectional view of the valve unit in which the spool is in a second advance position; 
         FIG. 6  is a cross-sectional view of the valve unit in which the spool is in a neutral position; 
         FIG. 7  is a cross-sectional view of the valve unit in which the spool is in a retard position; 
         FIG. 8  is a cross-sectional view showing a valve opening and closing timing control device according to a first alternative embodiment; 
         FIG. 9  is a cross-sectional view showing a valve opening and closing timing control device according to a second alternative embodiment; 
         FIG. 10  is a cross-sectional view taken along a line X-X of  FIGS. 8 and 9 ; and 
         FIG. 11  is a diagram listing a relationship between a position of a spool and supply and discharge of working oil according to another embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of a valve opening and closing timing control device disclosed here will be described below with reference to the drawings. However, this disclosure is not limited to the following embodiments, and various modifications can be made without departing from the scope of this disclosure. 
     [Basic Configuration] 
     As shown in  FIGS. 1 and 2 , a valve opening and closing timing control device A includes an external rotor  20  as a drive-side rotary body, an internal rotor  30  as a driven-side rotary body, and an electromagnetic control valve V that controls supply and discharge of working oil as a working fluid. Since the valve opening and closing timing control device A sets an opening and closing timing (opening and closing period) of an intake camshaft  5  (an example of a camshaft) of an engine E (an example of an internal combustion engine) of a vehicle such as a passenger car, the valve opening and closing timing control device A is provided coaxially with a rotation axis X of the intake camshaft  5 . 
     The internal rotor  30  (an example of the driven-side rotary body) is arranged coaxially with the rotation axis X of the intake camshaft  5  (external rotor  20 ), and is integrally rotated with the intake camshaft  5  by being coupled to the intake camshaft  5  by a coupling bolt  40  (an example of a valve case). The internal rotor  30  is provided inside the external rotor  20 . The external rotor  20  (an example of the drive-side rotary body) is arranged coaxially with the rotation axis X and rotates synchronously with a crankshaft  1  of the engine E. With this configuration, the external rotor  20  and the internal rotor  30  are relatively rotatable. 
     The valve opening and closing timing control device A includes a lock mechanism L that holds a relative rotation phase between the external rotor  20  and the internal rotor  30  (hereinafter simply referred to as “relative rotation phase”) at an intermediate lock phase M (an example of an intermediate phase) shown in  FIG. 2 . The intermediate lock phase M is a phase between a most retarded phase and a most advanced phase. The valve opening and closing timing control device A is controlled to shift to the intermediate lock phase M at the time of stop control of the engine E as an opening and closing timing suitable for starting the engine E. The shift control to the intermediate lock phase M may be executed when the engine E is started. 
     The electromagnetic control valve V includes an electromagnetic unit Va and a valve unit Vb supported by the engine E. 
     The electromagnetic unit Va includes a solenoid portion  50  and a plunger  51  that is arranged coaxially with the rotation axis X and protrudes and retracts by drive control of the solenoid portion  50 . In the valve unit Vb, a spool  55  that controls the supply and discharge of the working oil (an example of fluid) is arranged coaxially with the rotation axis X, and has a position relationship set such that a protrusion end of the plunger  51  abuts against an outer end of the spool  55 . 
     The electromagnetic control valve V sets a protrusion amount of the plunger  51  by controlling electric power supplied to the solenoid portion  50 , and operates the spool  55 . By this operation, the electromagnetic control valve V controls a flow of the working oil to set an opening and closing timing of an intake valve 5V, and performs switching between a lock state in which the lock mechanism L is restrained to the intermediate lock phase M and a lock release state in which the restraint of the intermediate lock phase M is released. A configuration and a control mode of the electromagnetic control valve V will be described later. 
     As shown in  FIG. 1 , the engine E is a four-cycle type engine in which a piston  3  is housed in a cylinder bore of a cylinder block  2  at an upper position, and the piston  3  and the crankshaft  1  are coupled by a coupling rod  4 . An upper portion of the engine E includes the intake camshaft  5  for opening and closing the intake valve 5V and an exhaust camshaft (not shown). 
     A support member  10  that rotatably supports the intake camshaft  5  is formed with a supply flow path  8  through which the working oil is supplied from a hydraulic pump P driven by the engine E. The hydraulic pump P supplies lubricating oil stored in an oil pan of the engine E to the valve unit Vb as the working oil through the supply flow path  8 . 
     A timing chain  7  is wound around an output sprocket  6  formed on the crankshaft  1  of the engine E and a timing sprocket  21 S of the external rotor  20 . Accordingly, the external rotor  20  rotates synchronously with the crankshaft  1 . A sprocket is also provided at a front end of the exhaust camshaft on an exhaust side, and the timing chain  7  is also wound around the sprocket. 
     As shown in  FIG. 2 , the external rotor  20  rotates in a drive rotation direction S by a driving force from the crankshaft  1 . A direction in which the internal rotor  30  rotates relative to the external rotor  20  in the same direction as the drive rotation direction S is referred to as an advance direction Sa, and a reverse direction to the direction is referred to as a retard direction Sb. In the valve opening and closing timing control device A, a relationship between the crankshaft  1  and the intake camshaft  5  is set such that an intake compression ratio is increased as a displacement amount when the relative rotation phase is displaced in the advance direction Sa increases, and the intake compression ratio is reduced as a displacement amount when the relative rotation phase is displaced in the retard direction Sb increases. 
     The present embodiment describes the valve opening and closing timing control device A provided on the intake camshaft  5 . The valve opening and closing timing control device A may be provided on the exhaust camshaft, and may be provided on both the intake camshaft  5  and the exhaust camshaft. 
     As shown in  FIG. 1 , the external rotor  20  includes an external rotor body  21 , a front plate  22 , and a rear plate  23 , which are integrated by fastening a plurality of fastening bolts  24 . The timing sprocket  21 S is formed on an outer periphery of the external rotor body  21 . 
     As shown in  FIG. 2 , a plurality of (three in the present embodiment) protrusion portions  21 T protruding inward in a radial direction are integrally formed on the external rotor body  21 . The internal rotor  30  includes a columnar internal rotor body  31  that is in close contact with the protrusion portions  21 T of the external rotor body  21 , and a plurality of vane portions  32  (three in the present embodiment) protruding outward in the radial direction from an outer periphery of the internal rotor body  31  so as to come into contact with an inner peripheral surface of the external rotor body  21 . 
     As described above, the internal rotor  30  is provided inside the external rotor  20 , and a plurality of (three in the present embodiment) fluid pressure chambers C are formed on an outer peripheral side of the internal rotor body  31  at positions between a pair of protrusion portions  21 T adjacent to each other in the rotation direction. The fluid pressure chambers C are partitioned by the vane portions  32 , and thus advance chambers Ca and retard chambers Cb are partitioned. Further, the internal rotor body  31  is formed with advance flow paths  33  communicating with the advance chambers Ca and retard flow paths  34  communicating with the retard chambers Cb. 
     As shown in  FIGS. 1 and 2 , the lock mechanism L includes a lock member  25  that is supported to be freely protruded and retracted in the radial direction with respect to each of the two protrusion portions  21 T of the external rotor  20 , a lock spring  26  that protrudes and biases the lock member  25 , and a lock recess  27  formed on the outer periphery of the internal rotor body  31 . A lock control flow path  35  communicating with the lock recess  27  is formed in the internal rotor body  31 . 
     The lock mechanism L functions to regulate the relative rotation phase to the intermediate lock phase M by simultaneously engaging the two lock members  25  with the corresponding lock recesses  27  by a biasing force of the lock spring  26 . By supplying the working oil to the lock control flow path  35  in this lock state, the lock member  25  is disengaged from the lock recess  27  against the biasing force of the lock spring  26  to release the lock state (lock release state). Conversely, by discharging the working oil from the lock control flow path  35 , the lock member  25  that receives the biasing force of the lock spring  26  is engaged with the lock recess  27  to allow the lock member  25  to shift to the lock state. 
     The lock mechanism L may be configured by engaging the single lock member  25  with the corresponding single lock recess  27 . Further, the lock mechanism L may have a configuration in which the lock member  25  is guided so as to move in the rotation axis X direction. 
     [Coupling Bolt] 
     As shown in  FIGS. 1 and 4 , the coupling bolt  40  (an example of the valve case) is integrally formed with a bolt body  41  which is generally tubular and a bolt head  42  on an outer end side (left side in  FIG. 4 ). An internal space  40 R that runs in the rotation axis X direction is formed inside the coupling bolt  40 , and a male screw portion  41 S is formed on an outer periphery of an inner end side (right side in  FIG. 4 ) of the bolt body  41 . An annular constriction portion  41 A, which is an annular groove along the outer periphery of the bolt body  41 , is formed on an outer end side of the bolt body  41  adjacent to the male screw portion  41 S. 
     As shown in  FIG. 1 , the intake camshaft  5  defines an axial internal space  5 R centered on the rotation axis X, and a female screw portion  5 S is formed on an inner periphery of the axial internal space  5 R. The axial internal space  5 R communicates with the supply flow path  8  and is supplied with the working oil from the hydraulic pump P. 
     With this configuration, the bolt body  41  is inserted into the internal rotor  30 , the male screw portion  41 S is screwed to the female screw portion  5 S of the intake camshaft  5 , and the internal rotor  30  is fastened to the intake camshaft  5  by the rotation operation of the bolt head  42 . By the fastening, the internal rotor  30  is fixed to the intake camshaft  5 , and the axial internal space  5 R and the internal space  40 R of the coupling bolt  40  (strictly, an internal space of a fluid supply pipe  54 ) communicate with each other. 
     As shown in  FIG. 4 , a regulation wall  44  is formed on the outer end side of the inner peripheral surface of the internal space  40 R of the coupling bolt  40  in the rotation axis X direction. The regulation wall  44  protrudes in a direction of approaching the rotation axis X. The regulation wall  44  regulates a protrusion position by abutting a land portion  55   b  on an outer end side of the spool  55 , which will be described later. In a region from an intermediate position of the coupling bolt  40  to an end portion on the outer end side thereof, a plurality of (four in the present embodiment) first drain flow paths D 1  are formed in an elongated hole shape (an example of a hole portion) with one end blocked along the rotation axis X. 
     In the bolt body  41 , a plurality of lock ports  41   c  (four in the present embodiment) communicating with the lock control flow path  35 , a plurality of (four in the present embodiment) advance ports  41   a  communicating with the advance flow path  33 , and a plurality of (four in the present embodiment) retard ports  41   b  communicating with the retard flow path  34  are formed as through holes connecting the internal space  40 R and the outer peripheral surface in order from the outer end side to the inner end side of the coupling bolt  40  (see also  FIG. 1 ). On an inner end side of the retard port  41   b  of the bolt body  41 , a plurality of (four in the present embodiment) second drain flow paths D 2  are formed as through holes connecting the internal space  40 R and the outer peripheral surface, and communicate with the annular constriction portion  41 A. The annular constriction portion  41 A communicates with a drain communication path  5 A formed through the end portion of the intake camshaft  5 , and the working oil from the second drain flow path D 2  is discharged to the outside through the drain communication path  5 A (see also  FIG. 1 ). That is, in the present embodiment, due to the configuration in which the first drain flow path D 1  extends in the rotation axis X direction and the second drain flow path D 2  extends in the radial direction orthogonal to the rotation axis X direction, the first drain flow path D 1  and the second drain flow path D 2  extend in directions intersecting each other at different positions in the rotation axis X direction. The drain communication path  5 A may be formed at an end portion of the internal rotor  30 , or may be formed at a boundary position between the internal rotor  30  and the intake camshaft  5 . 
     [Valve Unit] 
     As shown in  FIGS. 1 and 4 , the valve unit Vb includes the fluid supply pipe  54  that is coaxial with the rotation axis X and is housed in the internal space  40 R, and the spool  55  that is freely slidable in the rotation axis X direction while being guided by the inner peripheral surface of the coupling bolt  40  and an outer peripheral surface of a pipeline portion  54 T of the fluid supply pipe  54 . The valve unit Vb includes a spool spring  56  as a biasing member that biases the spool  55  in the protrusion direction, a check valve CV, an oil filter  59 , and a fixing ring  60 . 
     The fluid supply pipe  54  includes the pipeline portion  54 T inserted in the spool  55  and a flange-shaped base end portion  54 S at which the inner end side of the pipeline portion  54 T is bent in an annular shape. The pipeline portion  54 T and the base end portion  54 S are integrally formed. The base end portion  54 S abuts on a regulation step portion  41 D provided at a boundary position on the inner peripheral side between the male screw portion  41 S and the annular constriction portion  41 A of the coupling bolt  40 . In the pipeline portion  54 T, a plurality of (three in the present embodiment) first supply ports  54   a  are formed near the base end portion  54 S, and a plurality of (three in the present embodiment) second supply ports  54   b  are formed on the outer end side of the first supply ports  54   a.    
     The three first supply ports  54   a  are wide in the circumferential direction and have an elongated hole shape extending in the rotation axis X direction. Four intermediate hole portions  55   c  formed in the spool  55  at positions corresponding to the first supply ports  54   a  are circular. From such a configuration, the working oil from the pipeline portion  54 T can be reliably supplied to the intermediate hole portions  55   c.    
     Similar to the first supply ports  54   a , the second supply ports  54   b  also have an elongated hole shape extending in the rotation axis X direction. Four end hole portions  55   d  formed in the spool  55  at positions corresponding to the second supply ports  54   b  are circular. From such a configuration, the working oil can be reliably supplied from the pipeline portion  54 T to the end hole portions  55   d.    
     The spool  55  is formed with a spool body  55   a  which is tubular and has an abutting surface formed on the outer end side, and four land portions  55   b  formed on the outer periphery thereof in a protruding state. An internal flow path is formed inside the spool  55 . A plurality of (four in the present embodiment) intermediate hole portions  55   c  communicating with the internal flow path are formed at an intermediate position of the pair of land portions  55   b  on an inner end side in the rotation axis X direction. A plurality of (four in the present embodiment) end hole portions  55   d  communicating with the internal flow path are formed at the intermediate position of the pair of land portions  55   b  on an outer end side in the rotation axis X direction. An intermediate annular groove  55   f  that does not communicate with the internal flow path is formed at the intermediate position of the pair of land portions  55   b  between the intermediate hole portion  55   c  and the end hole portion  55   d . An elongated groove-shaped end annular groove  55   g  that does not communicate with the internal flow path is formed on an inner end side of the land portion  55   b  on an innermost end side in the rotation axis X direction. 
     The spool  55  is formed with an abutting end portion  55   r  that abuts on the base end portion  54 S of the fluid supply pipe  54  to determine an operation limit when the spool  55  is operated in a pushing direction. The abutting end portion  55   r  is provided at an end portion of a region where the spool body  55   a  is extended. Even when the spool  55  is pushed in with an excessive force, a defect that the spool  55  operates beyond the operation limit is prevented. 
     The spool spring  56  is a compression coil type spring, and is arranged between a bottom wall  55   e  on an outer end side of the spool  55  and a bottom wall  54 Ta on an outer end side of the pipeline portion  54 T of the fluid supply pipe  54 . When the electric power is not supplied to the solenoid portion  50  of the electromagnetic unit Va due to an action of the biasing force, the land portion  55   b  on the outer end side abuts on the regulation wall  44  and the spool  55  is maintained at a first advance position PA 1  shown in  FIG. 4 . 
     [Check Valve] 
     The check valve CV includes an opening plate  57  and a valve plate  58  which are formed of metal plates having an equal outer diameter, a guide member  61 , a tubular member  62 , and a valve spring  63 . An annular opening portion  57   a  centered on the rotation axis X is formed at an outer peripheral position of the opening plate  57 . A circular valve body  58   a  having a diameter larger than that of the opening portion  57   a  is arranged at the outer peripheral position of the valve plate  58 , and a circular opening portion  58   b  centered on the rotation axis X is formed at a center position. 
     The guide member  61  includes a bottom portion  61   a  and a tubular protrusion portion  61   b  protruding from the bottom portion  61   a . A plurality of slits  61   ba  are formed on a side wall of the protrusion portion  61   b . The protrusion portion  61   b  is inserted into the opening portion  58   b  of the valve plate  58 , and the valve plate  58  is guided by the protrusion portion  61   b  and moves. The tubular member  62  includes a bottom portion  62   a  and an annular portion  62   b  that protrudes annularly from an outer periphery of the bottom portion  62   a . An opening portion  62   a   1  having substantially the same diameter as the inner diameter of the pipeline portion  54 T of the fluid supply pipe  54  is formed at the center of the bottom portion  62   a . The opening plate  57 , the valve plate  58 , the guide member  61 , and the valve spring  63  are housed inside the annular portion  62   b , and the oil filter  59  abuts on the end portion of the annular portion  62   b.    
     The valve spring  63  is a compression coil type spring and is arranged between the bottom portion  61   a  of the guide member  61  and the valve body  58   a  of the valve plate  58 . The check valve CV is configured such that, when pressure downstream increases or when discharge pressure of the hydraulic pump P decreases, the valve body  58   a  comes into close contact with the opening plate  57  by the biasing force of the valve spring  63  to close the opening portion  57   a.    
     The oil filter  59  has a structure in which a metal net body is reinforced with a resin frame, and removes dust contained in the working oil. The fixing ring  60  is press-fitted and fixed to an inner periphery of the end portion of the coupling bolt  40 , and positions of the oil filter  59 , the opening plate  57 , and the valve plate  58  are determined by the fixing ring  60 . The tubular member  62 , the guide member  61 , the valve spring  63 , the opening plate  57 , and the valve plate  58  constituting the check valve CV are arranged in this order, the oil filter  59  is arranged in the internal space  40 R so as to be further overlapped, and the fixing ring  60  is press-fitted and fixed to the inner periphery of the internal space  40 R. 
     In this way, by fixing with the fixing ring  60 , the base end portion  54 S of the fluid supply pipe  54  is sandwiched and fixed between the bolt body  41  and the tubular member  62 . Due to the biasing force of the spool spring  56  that abuts on the bottom wall  54 Ta of the fluid supply pipe  54 , the land portion  55   b  on the outer end side of the spool  55  abuts on the regulation wall  44 , and a position in the rotation axis X direction is determined. 
     [Operation Mode] 
     In the valve opening and closing timing control device A, when the electric power is not supplied to the solenoid portion  50  of the electromagnetic unit Va, no pressing force acts on the spool  55  from the plunger  51 , and a position of the spool  55  is maintained in a state where the land portion  55   b  at the outer side position abuts on the regulation wall  44  by the biasing force of the spool spring  56  as shown in  FIG. 4 . 
     A movement start position of the spool  55  is the first advance position PA 1 . By increasing the electric power supplied to the solenoid portion  50  of the electromagnetic unit Va, as shown in  FIG. 3 , the spool  55  can be freely operated to the second advance position PA 2 , the neutral position PN, and the retard position PB in this order. That is, by setting the electric power supplied to the solenoid portion  50  of the electromagnetic unit Va, the spool  55  can be operated to any one of the four operation positions. When the spool  55  is operated to the retard position PB, the spool  55  is at the movement end position that maximizes the electric power supplied to the solenoid portion  50 . 
     Further, in the valve unit Vb, the first advance position PA 1  is set to a lock position. In this lock position, the lock mechanism L can shift to the lock state. When the spool  55  is operated to one of the first advance position PA 1  and the second advance position PA 2 , the working oil supplied from the hydraulic pump P is sent to the advance port  41   a  through the intermediate hole portion  55   c  of the spool  55 , and is further supplied to the advance chamber Ca from the advance flow path  33 . At the same time, the working oil in the retard chamber Cb flows from the retard flow path  34  to the retard port  41   b , and is discharged from the second drain flow path D 2  through the end annular groove  55   g  of the spool  55  to the outside through the annular constriction portion  41 A and the drain communication path  5 A. 
     In the first advance position PA 1 , as shown in  FIG. 4 , in cooperation with the supply of the working oil to the advance chamber Ca and the discharge of the working oil from the retard chamber Cb, the working oil in the lock recess  27  flows from the lock control flow path  35  to the lock port  41   c , and is discharged from the first drain flow path D 1  through the intermediate annular groove  55   f  of the spool  55 . As a result, when the vane portion  32  of the internal rotor  30  moves in the advance direction Sa and reaches the intermediate lock phase M, the lock member  25  engages with the lock recess  27  by the biasing force of the lock spring  26  to be in the lock state. 
     In the second advance position PA 2 , as shown in  FIG. 5 , in cooperation with the supply of the working oil to the advance chamber Ca, the working oil flows from the lock port  41   c  to the lock recess  27  through the lock control flow path  35 , and the pressure of the working oil is applied to the lock member  25 . As a result, the operation in the advance direction Sa is continuously performed in a state where the lock of the lock mechanism L is released. 
     When the spool  55  is operated to the neutral position PN, as shown in  FIG. 6 , the pair of land portions  55   b  are in such a position relationship that the advance port  41   a  and the retard port  41   b  are closed, and the supply and discharge of the working oil to the advance chamber Ca and the retard chamber Cb are cut off, and the relative rotation phase is maintained. In the neutral position PN, the working oil flows from the lock port  41   c  to the lock recess  27  through the lock control flow path  35 , the pressure of the working oil is applied to the lock member  25 , and the state where the lock of the lock mechanism L is released continues. 
     When the spool  55  is operated to the retard position PB, as shown in  FIG. 7 , the working oil supplied from the hydraulic pump P is sent to the retard port  41   b  through the intermediate hole portion  55   c  of the spool  55 , and is further supplied to the retard chamber Cb from the retard flow path  34 . At the same time, the working oil in the advance chamber Ca flows from the advance flow path  33  to the advance port  41   a , and is discharged from the first drain flow path D 1  through the intermediate annular groove  55   f  of the spool  55 . 
     In this way, in any of the four operation positions, the working oil of the lock mechanism L and the working oil of the advance chamber Ca or the retard chamber Cb are not discharged to the first drain flow path D 1  at the same time, and the same applies to the second drain flow path D 2 . Therefore, it is possible to smoothly discharge the working oil from the lock mechanism L and to reliably shift to the lock state. In addition, it is possible to smoothly discharge the working oil from the advance chamber Ca or the retard chamber Cb to improve the responsiveness of the phase control. 
     In the present embodiment, the first drain flow path D 1  through which the working oil is discharged from the advance chamber Ca through the spool  55  and the second drain flow path D 2  through which the working oil is discharged from the retard chamber Cb through the spool  55  extend in directions intersecting each other at different positions in the rotation axis X direction of the coupling bolt  40 . As a result, it is possible to sufficiently ensure locations for providing the drain flow paths D 1  and D 2  on the coupling bolt  40 , and it is possible to increase a flow path cross-sectional area of the first drain flow path D 1  and the second drain flow path D 2 . Therefore, the flow path cross-sectional area of the drain flow paths D 1  and D 2  through which the working oil is discharged from the advance chamber Ca or the retard chamber Cb can be increased to improve the responsiveness of the phase control. In addition, since the discharge of the working oil from the lock mechanism L is also used in the first drain flow path D 1 , it is not necessary to separately provide a lock drain flow path extending in the rotation axis X direction of the coupling bolt  40 , so that a sufficient flow path cross-sectional area of the first drain flow path D 1  can be ensured. 
     Hereinafter, only a configuration different from the above-described embodiment will be described as other embodiments. In order to facilitate understanding of the drawings, the same members as those in the embodiment described above are denoted by the same reference numerals. 
     First Alternative Embodiment 
     As the lock mechanism L in the above-described embodiment, a configuration that locks at a most advanced phase or a most retarded phase may be adopted instead of the configuration that locks at the intermediate lock phase M. An embodiment that locks at the most retarded phase is shown in  FIGS. 8 to 11 . As shown in  FIGS. 8 and 10 , a communication path  29  for communicating the lock recess  27  and the advance chamber Ca is provided. Working oil is supplied or discharged to the lock recess  27  through the communication path  29  in cooperation with supply or discharge of the working oil to the advance chamber Ca. In the present embodiment, as in the above-described embodiment, the lock port  41   c  of the bolt body  41  and the end hole portion  55   d  of the spool  55  are not provided so that an axial length of the valve opening and closing timing control device A can be shortened to achieve a compact size. 
     In the present embodiment, the spool  55  has three operation positions (see  FIG. 11 ). That is, a movement start position of the spool  55  is an advance position PA. By increasing electric power supplied to the solenoid portion  50  of the electromagnetic unit Va, the spool  55  can be freely operated to the neutral position PN and the retard position PB including a movement end position of the spool  55  in this order. 
     In the advance position PA of the spool  55 , in cooperation with the supply of working oil to the advance chamber Ca, the working oil supplied to the advance chamber Ca is also supplied to the lock recess  27  through the communication path  29  (see  FIGS. 8 and 10 ). At the same time, the working oil in the retard chamber Cb flows from the retard flow path  34  to the retard port  41   b , and is discharged from the second drain flow path D 2  through the end annular groove  55   g  of the spool  55  to the outside through the annular constriction portion  41 A and the drain communication path  5 A. As a result, the operation in the advance direction Sa is continuously performed in a state where the lock of the lock mechanism L is released. When the spool  55  is operated to the neutral position PN, the supply and discharge of the working oil to the advance chamber Ca and the lock recess  27  and the retard chamber Cb are cut off, and the relative rotation phase is maintained. 
     When the spool  55  is operated to the retard position PB, the working oil is supplied to the retard chamber Cb, and in cooperation with the discharge of the working oil from the advance chamber Ca, the working oil in the lock recess  27  flows from the advance flow path  33  to the advance port  41   a  through the communication path  29 , and is discharged from the first drain flow path D 1  through the intermediate annular groove  55   f  of the spool  55 . As a result, when the vane portion  32  of the internal rotor  30  moves in the retard direction Sb and reaches the most retarded phase, the lock member  25  engages with the lock recess  27  by the biasing force of the lock spring  26  to be in the lock state (see  FIG. 10 ). 
     Second Alternative Embodiment 
     In the present embodiment, as shown in  FIG. 9 , a plurality of drain grooves  55   ba  (an example of the outer end portion) are formed on an outer surface of the land portion  55   b  on an outer end side of the spool  55 . The drain grooves  55   ba  communicate with the intermediate annular groove  55   f  of the spool  55 . That is, the first drain flow path D 1  in the first alternative embodiment is formed between an outer end of the spool  55  including the drain groove  55   ba  and the bolt body  41 . Similar to the embodiments described above, the second drain flow path D 2  in the present embodiment is constituted by a through hole (through hole connecting the internal space  40 R of the bolt body  41  and the outer peripheral surface of the bolt body  41 ) of the bolt body  41  in a direction intersecting the rotation axis X direction. 
     Since the advance position PA and the neutral position PN of the spool  55  are the same as those in the first alternative embodiment, a description thereof will be omitted. When the spool  55  is operated to the retard position PB, the working oil is supplied to the retard chamber Cb, and in cooperation with the discharge of the working oil from the advance chamber Ca, the working oil in the lock recess  27  flows from the advance flow path  33  to the advance port  41   a  through the communication path  29 , and is discharged from the first drain flow path D 1  including the drain groove  55   ba  through the intermediate annular groove  55   f  of the spool  55 . As a result, when the vane portion  32  of the internal rotor  30  moves in the retard direction Sb and reaches the most retarded phase, the lock member  25  engages with the lock recess  27  by the biasing force of the lock spring  26  to be in the lock state. 
     Other Embodiments 
     (1) If the first drain flow path D 1  and the second drain flow path D 2  in the above-described embodiments extend in directions intersecting each other at different positions in the rotation axis X direction, the first drain flow path D 1  may be inclined with respect to the rotation axis X direction, or the second drain flow path D 2  may be inclined with respect to the radial direction. 
     (2) In the above-described embodiments, the bolt body  41  is fixed to the intake camshaft  5  by screwing the male screw portion  41 S formed on the bolt body  41  of the coupling bolt  40  as a tubular valve case into the female screw portion  5 S of the intake camshaft  5 . Alternatively, for example, the valve unit Vb and the check valve CV may be housed in the tubular valve case fixed to the intake camshaft  5  by press-fitting or the like. 
     (3) The first advance position PA 1  described above may be set as the movement end position of the spool  55 , and the retard position PB may be set as the movement start position of the spool  55 . When the retard position PB is the movement end position of the spool  55 , a lock mode may be provided in which, in cooperation with the discharge of the working oil from the advance chamber Ca and the supply of working oil to the retard chamber Cb, the working oil of the lock recess  27  flows from the lock control flow path  35  to the lock port  41   c  and is discharged from the first drain flow path D 1  through the intermediate annular groove  55   f  of the spool  55 . In this case, the working oil from the advance chamber Ca and the working oil from the lock mechanism L are discharged from the first drain flow path D 1  at the same time. The spool  55  has five operation positions in which a lock mode at the retard position is added to the above four operation positions. 
     (4) The advance position PA in the first and second alternative embodiments described above may be set as the movement end position of the spool  55 , and the retard position PB may be set as the movement start position of the spool  55 . 
     (5) As compared with the embodiments described above, the valve unit Vb may be configured such that the arrangement of the advance port  41   a  and the retard port  41   b  is reversed. 
     (6) In the embodiments described above, the first drain flow path D 1  may be constituted by a through hole of the coupling bolt  40  in a direction intersecting the rotation axis X direction. 
     (7) The lock mechanism L in the embodiments described above can be restrained by any one of the intermediate lock phase M, the most retarded phase, and the most advanced phase. Alternatively, the lock mechanism L may be a multi-lock system capable of restraining the relative rotation phase at a plurality of phases. 
     INDUSTRIAL APPLICABILITY 
     Embodiments disclosed here can be used in a valve opening and closing timing control device that controls a relative rotation phase between a drive-side rotary body and a driven-side rotary body by fluid pressure. 
     A characteristic configuration of a valve opening and closing timing control device according to an aspect of this disclosure resides in that the valve opening and closing timing control device includes a drive-side rotary body that rotates synchronously with a crankshaft of an internal combustion engine; a driven-side rotary body that is provided inside the drive-side rotary body in a state of being coaxial with a rotation axis of the drive-side rotary body and that rotates integrally with a camshaft for opening and closing a valve; an advance chamber and a retard chamber formed between the drive-side rotary body and the driven-side rotary body; a valve unit that includes a spool movable in a rotation axis direction and that controls supply and discharge of fluid to and from the advance chamber and the retard chamber; a tubular valve case that has an internal space extending along the rotation axis inside the driven-side rotary body in a radial direction and that houses the valve unit in the internal space; a first drain flow path through which the fluid is discharged from any one of the advance chamber or the retard chamber through the spool; and a second drain flow path through which the fluid is discharged from the other one of the advance chamber or the retard chamber through the spool, in which the first drain flow path and the second drain flow path extend in directions intersecting each other at different positions in the rotation axis direction. 
     In this configuration, since the valve unit is provided in the internal space of the valve case in the rotation axis direction inside the driven-side rotary body in the radial direction, the device can achieve a compact size compared with a case where the valve unit is provided outside the driven-side rotary body. When a single spool is constituted as in the valve opening and closing timing control device described in Reference 1 in order to achieve a more compact size, a flow path configuration of the advance chamber and the retard chamber are complicated. Accordingly, it is important to ensure a flow path cross-sectional area of a phase control drain flow path (advance chamber drain flow path and retard chamber drain flow path) in order to improve the responsiveness of the phase control. 
     Therefore, in this configuration, for example, the first drain flow path through which the fluid is discharged from the advance chamber through the spool and the second drain flow path through which the fluid is discharged from the retard chamber through the spool extend in directions intersecting each other at different positions in the rotation axis X direction. As a result, it is possible to sufficiently ensure locations for providing the drain flow path, and it is possible to increase the flow path cross-sectional area of the first drain flow path and the second drain flow path. Therefore, it is possible to provide the valve opening and closing timing control device capable of increasing the flow path cross-sectional area of the drain flow path through which the fluid is discharged from the advance chamber or the retard chamber to improve the responsiveness of the phase control. 
     Another characteristic configuration resides in that, in the valve case, the first drain flow path is formed to extend in the rotation axis direction and the second drain flow path is formed to extend in a radial direction orthogonal to the rotation axis direction. 
     As in this configuration, in the valve case, when the first drain flow path extends in the rotation axis direction and the second drain flow path extends in the radial direction and both drain flow paths are orthogonal to each other, the flow path cross-sectional area of the first drain flow path and the second drain flow path can be further ensured, and the valve case can be easily processed. 
     Another characteristic configuration resides in that the valve opening and closing timing control device includes a lock mechanism that restrains a relative rotation phase of the driven-side rotary body with respect to the drive-side rotary body to an intermediate phase between a most retarded phase and a most advanced phase, in which the fluid supplied to the lock mechanism is discharged from the first drain flow path. 
     As in this configuration, the fluid discharge from the lock mechanism is also used in the first drain flow path. Accordingly, it is not necessary to separately provide a lock drain flow path extending in the rotation axis direction of the valve case. Therefore, a sufficient flow path cross-sectional area of the first drain flow path can be ensured. Further, since it is possible to discharge the fluid of the lock mechanism from the first drain flow path while discharging the fluid of the advance chamber or the retard chamber from the second drain flow path, shift to the intermediate phase can be performed smoothly. 
     Another characteristic configuration resides in that the valve opening and closing timing control device includes a lock mechanism that restrains a relative rotation phase of the driven-side rotary body with respect to the drive-side rotary body to a most retarded phase or a most advanced phase, in which the fluid supplied to the lock mechanism is discharged from the first drain flow path. 
     As in this configuration, since the fluid discharge from the lock mechanism is also used in the first drain flow path, it is not necessary to separately provide a lock drain flow path extending in the rotation axis direction of the valve case. Therefore, a sufficient flow path cross-sectional area of the first drain flow path can be ensured. 
     Another characteristic configuration resides in that the second drain flow path includes a through hole of the valve case along a direction intersecting the rotation axis direction. 
     Since the second drain flow path in this configuration is constituted by the through hole of the valve case in the direction intersecting the rotation axis direction, the flow path cross-sectional area can be sufficiently ensured. 
     Another characteristic configuration resides in that the first drain flow path includes a hole portion along the rotation axis direction of the valve case. 
     As in this configuration, if the first drain flow path is constituted by the hole portion in the rotation axis direction of the valve case, the size of the hole portion may be changed according to a required flow path cross-sectional area, and the flow path can be easily designed. 
     Another feature configuration resides in that the first drain flow path is formed between an outer end portion of the spool and the valve case. 
     As in this configuration, if the first drain flow path is formed between the outer end portion of the spool and the valve case, processing is easier than when the first drain flow path is formed in the rotation axis direction of the valve case. 
     Another characteristic configuration resides in that, when the spool is at one of a movement start position or a movement end position, the fluid is discharged from the first drain flow path, and when the spool is at the other one of the movement start position or the movement end position, the fluid is discharged from the second drain flow path. 
     As in this configuration, if the first drain flow path and the second drain flow path are provided when the spool is at the movement start position and movement end position, positions of the phase control drain flow path can be easily set. 
     The principles, preferred embodiment and mode of operation of the present invention have been described in the foregoing specification. However, the invention which is intended to be protected is not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. Variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present invention. Accordingly, it is expressly intended that all such variations, changes and equivalents which fall within the spirit and scope of the present invention as defined in the claims, be embraced thereby.