Patent Publication Number: US-9850788-B2

Title: Valve timing controller

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is based on Japanese Patent Application No. 2015-76210 filed on Apr. 2, 2015, the disclosure of which is incorporated herein by reference in its entirety. 
     TECHNICAL FIELD 
     The present disclosure relates to a valve timing controller. 
     BACKGROUND 
     A valve timing controller controls a rotation phase between a driving rotor rotating with a crankshaft and a driven rotor rotating with a camshaft using planetary movement of a planetary rotor. 
     In JP 4360426 B (US 2009/0017952 A1), a driven rotor is connected coaxially with a camshaft which supports a driving rotor from a radially inner side (radial bearing), and supports the driving rotor on both sides in the axial direction (thrust bearing) and from a radially inner side (radial bearing). A planetary rotor is arranged eccentric to the driving rotor and the driven rotor, and is able to control the rotation phase by planetary movement due to a gear engagement state on the eccentric side from the radially inner side. The planetary movement of the planetary rotor can be realized smoothly by a planetary carrier that supports the driving rotor from a radially inner side (radial bearing). The control responsivity of the valve timing according to the rotation phase is improved in the valve timing controller. 
     Furthermore, the planetary rotor is biased to the eccentric side relative to the driving rotor and the driven rotor by the restoring force of an elastic component interposed between the planetary carrier and the planetary rotor. Thereby, the rattling noise is controlled at the engagement part of the planetary rotor relative to the driving rotor and the driven rotor. 
     SUMMARY 
     It is an object of the present disclosure to provide a valve timing controller in which abnormal noise can be reduced. 
     According to an aspect of the present disclosure, a valve timing controller that controls valve timing of a valve opened and closed by a camshaft using a torque transferred from a crankshaft for an internal-combustion engine includes a driving rotor, a driven rotor, a planetary rotor, a planetary carrier, and an elastic component. The driving rotor rotates with the crankshaft in a state where the driving rotor is supported by the camshaft from an inner side in a radial direction. The driven rotor rotates with the camshaft in a state where the driven rotor supports the driving rotor on both sides in an axial direction and where the driven rotor supports the driving rotor from an inner side in a radial direction. The driven rotor is connected coaxially with the camshaft. The planetary rotor is arranged eccentric relative to the driving rotor and the driven rotor, and controls a rotation phase between the driving rotor and the driven rotor by carrying out planetary movement under a gear engagement state in which the planetary rotor is engaged with the driving rotor and the driven rotor from an inner side in the radial direction on an eccentric side. The planetary carrier causes the planetary movement of the planetary rotor under a state where the driving rotor is supported from the inner side in the radial direction, and where the planetary rotor is supported from the inner side in the radial direction. The elastic component is interposed between the planetary rotor and the planetary carrier to produce a restoring force biasing the planetary rotor to the eccentric side such that the driving rotor is inclined to the driven rotor. The driving rotor has an inclination angle θ 1  relative to the driven rotor in a first inclination state where the driving rotor is in contact with the driven rotor on both sides in the axial direction. The driving rotor has an inclination angle θ 2  relative to the driven rotor in a second inclination state where the driving rotor is in contact with the driven rotor on both sides in the radial direction. The driving rotor has an inclination angle θ 3  relative to the driven rotor in a third inclination state where the driving rotor is in contact with the camshaft on both sides in the radial direction. A relation of θ 1 &lt;θ 2  and a relation of θ 1 &lt;θ 3  are satisfied. 
     Accordingly, the inclination angle θ 1  in the first inclination state is smaller than the inclination angle θ 2  in the second inclination state, and is smaller than the inclination angle θ 3  in the third inclination state, while the driving rotor is inclined to the driven rotor by the restoring force of the elastic component. Therefore, among the three kinds of assumed inclination states, the first inclination state is realized in fact, and the second inclination state and the third inclination state can be restricted. This means that the driving rotor can maintain, against the restoring force of the elastic component, to be in contact with the driven rotor on the both sides in the axial direction, prior to the contact with the driven rotor and the camshaft in the radial direction. Therefore, the driving rotor can be restricted from moving to the driven rotor in the axial direction, such that noise caused by a collision of the rotors can be controlled. 
     In other words, noise caused when the driving rotor collides with the driven rotor can be restricted, while abnormal noise caused by a backlash can be restricted by setting the position of the engagement part of the planetary rotor relative to the driving rotor and the driven rotor. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The above and other objects, features and advantages of the present disclosure will become more apparent from the following detailed description made with reference to the accompanying drawings. In the drawings: 
         FIG. 1  is a view illustrating a valve timing controller according to an embodiment; 
         FIG. 2  is a sectional view taken along a line II-II of  FIG. 1 ; 
         FIG. 3  is a sectional view taken along a line of  FIG. 1 ; 
         FIG. 4  is an enlarged sectional view taken along a line IV-IV of  FIG. 2 ; 
         FIG. 5  is a diagram explaining a first inclination state assumed in a phase adjustment unit of  FIG. 1 ; 
         FIG. 6  is a diagram explaining a second inclination state assumed in the phase adjustment unit of  FIG. 1 ; 
         FIG. 7  is a diagram explaining a third inclination state assumed in the phase adjustment unit of  FIG. 1 ; and 
         FIG. 8  is a sectional view illustrating a modification in the embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Embodiments of the present disclosure will be described hereafter referring to drawings. In the embodiments, a part that corresponds to a matter described in a preceding embodiment may be assigned with the same reference numeral, and redundant explanation for the part may be omitted. When only a part of a configuration is described in an embodiment, another preceding embodiment may be applied to the other parts of the configuration. The parts may be combined even if it is not explicitly described that the parts can be combined. The embodiments may be partially combined even if it is not explicitly described that the embodiments can be combined, provided there is no harm in the combination. 
     As shown in  FIG. 1 , a valve timing controller  1  according to an embodiment is attached to a transfer system which transmits crank torque to a camshaft  2  from a crankshaft (not shown) in an internal-combustion engine of a vehicle. The camshaft  2  opens and closes an intake valve (not shown) using transfer of crank torque as a valve of the internal-combustion engine. The valve timing controller  1  controls the valve timing of the intake valve. 
     As shown in  FIGS. 1-3 , the valve timing controller  1  includes an actuator  4 , a circuit unit  7 , and a phase adjustment unit  8 . 
     As shown in  FIG. 1  that includes a sectional view taken along a line I-I of  FIG. 2 , the actuator  4  is an electric motor such as brushless motor, and has a housing body  5  and a control shaft  6 . The housing body  5  is fixed to a fix portion of the internal-combustion engine, and supports the control shaft  6  in a rotatable state. The circuit unit  7  includes a drive driver and a microcomputer for control, and is arranged outside and/or inside the housing body  5 . The circuit unit  7  is electrically connected to the actuator  4 , and controls power supply to the actuator  4  to rotate the control shaft  6 . 
     As shown in  FIGS. 1-3 , the phase adjustment unit  8  includes a driving rotor  10 , a driven rotor  20 , a planetary rotor  30 , a planetary carrier  50 , and an elastic component  60 . 
     The driving rotor  10  is made of metal, and has a hollow shape as a whole. The driven rotor  20 , the planetary rotor  30 , the planetary carrier  50 , and the elastic component  60  of the phase adjustment unit  8  are held inside the driving rotor  10 . As shown in  FIGS. 1, 2, and 4 , the driving rotor  10  includes a sun gear  11 , a sprocket  13 , and a drive bearing  15 . 
     The sun gear  11  has a cylindrical shape with a projection. The sprocket  13  has a based cylindrical shape. The sun gear  11  is rotatable integrally with the sprocket  13 . The sun gear  11  and the sprocket  13  are tightened with each other. The sun gear  11  has a drive side internal-gear part  12  with a tip circle on the radially inner side of a root circle. The drive side internal-gear part  12  is defined on the large diameter side inner circumference of the circumference wall part. As shown in  FIG. 1 , the sun gear  11  has a journal part  14  on the small diameter side inner circumference of the circumference wall part. The journal part  14  is located opposite from the camshaft  2  through the drive side internal-gear part  12  in the axial direction. 
     The sprocket  13  is arranged coaxially with the camshaft  2 . The camshaft  2  is made of metal, and has a cylindrical shape. The sprocket  13  is located on the radially outer side of the camshaft  2 . In other words, a radial bearing is defined between the sprocket  13  and the camshaft  2 . An inner circumference surface  13   b  of a bottom wall part of the sprocket  13  is slidably fitted to the outer circumference surface  2   a  of the camshaft  2 , such that a radial bearing is defined. Specifically, the inner circumference surface  13   b  is supported by the camshaft  2  from the inner side in the radial direction. In this state, the camshaft  2  extends from the radially inner side of the sprocket  13  in the axial direction away from the sun gear  11 . Moreover, the sprocket  13  has a projection part  18  projected toward the sun gear  11  in the axial direction. The projection part  18  has a circular shape continuing in the circumferential direction. The projection part  18  is defined on the inner bottom surface of the bottom wall part of the sprocket  13 . The projection part  18  is located on the radially inner side of the large diameter side end surface  11   a  of the circumference wall part of the sun gear  11 . 
     The sprocket  13  has plural sprocket teeth  19  on the outer circumference surface of the circumference wall part. The sprocket teeth  19  are projected outward in the radial direction, and are arranged in the circumferential direction with a regular interval. A timing chain (not shown) is disposed between the sprocket teeth  19  of the sprocket  13  and plural sprocket teeth of the crankshaft, such that the sprocket  13  and the crankshaft are engaged with each other. A crank torque outputted from the crankshaft is transmitted to the sprocket  13  through the timing chain. As the result, the driving rotor  10  is rotated with the crankshaft in a fixed direction (counterclockwise in  FIG. 2 , clockwise in  FIG. 3 ) while the driving rotor  10  is supported by the camshaft  2  in the radial direction. 
     The drive bearing  15  is coaxially arranged on the radially inner side of the journal part  14 . The drive bearing  15  has a circular shape and is made of metal. The drive bearing  15  is a single sequence type radial bearing in which one row of spherical rolling elements  15   c  are arranged between the outer wheel  15   a  and the inner wheel  15   b . The outer wheel  15   a  is coaxially press-fitted to the inner circumference surface  14   a  of the journal part  14 , such that the sun gear  11  and the drive bearing  15  can rotate integrally with each other. 
     As shown in  FIGS. 1 and 3 , the driven rotor  20  having the based cylindrical shape made of metal is coaxially arranged on the radially inner side of the sprocket  13 . In other words, the driven rotor  20  supports the driving rotor  10  in the radial direction as a radial bearing. Of the circumference wall part of the driven rotor  20  shown in  FIG. 1 , the bottom wall side outer circumference surface  20   a  is slidably fitted with the bottom wall side inner circumference surface  13   a  of the circumference wall part of the sprocket  13 , such that the bottom wall side outer circumference surface  20   a  supports the driving rotor  10  from the radially inner side as a radial bearing. 
     The driven rotor  20  is supported between the sun gear  11  and the sprocket  13  in the axial direction, and supports the driving rotor  10  on both sides in the axial direction as a thrust bearing. An opening end surface  20   b  of the circumference wall part of the driven rotor  20  is in contact with the large diameter side end surface  11   a  of the circumference wall part of the sun gear  11 , and supports the driving rotor  10  from a side adjacent to the camshaft  2  in the axial direction as a thrust bearing. On the other hand, an outer end surface  20   c  of the bottom wall part of the driven rotor  20  is in contact with the tip end surface  18   a  of the projection part  18  of the bottom wall part of the sprocket  13 , and supports the driving rotor  10  from the opposite side of the camshaft  2  in the axial direction as a thrust bearing. 
     As shown in  FIGS. 1 and 3 , the driven rotor  20  has a connection part  22  at the central part of the bottom wall part to be connected with the camshaft  2  coaxially. The driven rotor  20  rotating in the same direction (clockwise in  FIG. 3 ) can rotate relative to the driving rotor  10  under the state where the driven rotor  20  supports the driving rotor  10  on the both sides in the axial direction (thrust bearing) and from the inner side in the radial direction (radial bearing). 
     The driven rotor  20  has a driven side internal-gear part  24  with a tip circle on the radially inner side of a root circle. The driven side internal-gear part  24  is defined on the opening side inner circumference surface of the circumference wall part. The driven side internal-gear part  24  is arranged offset relative to the drive side internal-gear part  12  toward the camshaft  2  in the axial direction, not to overlap in the radial direction. The inside diameter of the driven side internal-gear part  24  is set smaller than the inside diameter of the drive side internal-gear part  12 . The number of teeth of the driven side internal-gear part  24  is set less than the number of teeth of the drive side internal-gear part  12 . 
     As shown in  FIGS. 1-4 , the planetary rotor (gear rotor)  30  having a disk shape, as a whole, made of metal is arranged eccentric to the rotors  10  and  20 . The planetary rotor  30  has a planetary gear  31  and a planetary bearing  36 . 
     As shown in  FIGS. 1-3 , the planetary gear  31  is arranged to extend from the radially inner side of the driven rotor  20  to the radially inner side of the drive side internal-gear part  12 . The planetary gear  31  is made of metal, and has a ring shape with a projection. The planetary gear  31  has the external-gear part  32 ,  34  with a tip circle on the radially outer side of a root circle, around the outer circumference surface of the circumference wall part. The drive side external-gear part  32  is engaged with the drive side internal-gear part  12  from the radially inner side on the eccentric side where the planetary gear  31  is eccentric to the rotors  10  and  20 . The driven side external-gear part  34  is formed at a position not overlapping with the drive side external-gear part  32  in the radial direction. Specifically, the driven side external-gear part  34  is positioned to shift toward the camshaft  2  in the axial direction, relative to the drive side external-gear part  32 . The outer diameter of the driven side external-gear part  34  is different from that of the drive side external-gear part  32 , and is smaller than the outer diameter of the drive side external-gear part  32 . The number of teeth of the driven side external-gear part  34  is set less than the number of teeth of the drive side external-gear part  32 . The driven side external-gear part  34  is engaged with the driven side internal-gear part  24  from the radially inner side on the eccentric side. 
     As shown in  FIG. 1 , compared with the center Cr of the radial bearing part Pr in the axial direction where the sprocket  13  is supported by the driven rotor  20 , the center Cbs of the engagement part Pbs between the driven side external-gear part  34  and the driven side internal-gear part  24  in the axial direction is shifted away from the camshaft  2  in the axial direction. The axial center Cbs of the engagement part Pbs represents a center of an area where the driven side external-gear part  34  and the driven side internal-gear part  24  are actually engaged and overlapped with each other in the axial direction. The axial center Cr of the radial bearing part Pr represents a center of an area where the circumference surfaces  13   a ,  20   a  of the sprocket  13  and the driven rotor  20  are slidingly overlapped with each other actually in the axial direction. 
     As shown in  FIGS. 1-3 , the planetary bearing  36  is arranged to extend from the radially inner side of the drive side external-gear part  32  to the radially inner side of the driven side external-gear part  34 . The planetary bearing  36  is made of metal, and has a circular shape. The planetary bearing  36  is a single sequence type radial bearing in which one row of spherical rolling elements  36   c  is interposed between the outer wheel  36   a  and the inner wheel  36   b . The outer wheel  36   a  is coaxially press-fitted to the inner circumference surface  31   a  of the planetary gear  31 , such that the planetary gear  31  and the planetary bearing  36  are integrally able to have planetary movement. 
     The planetary carrier  50  is made of metal, and has a partially-eccentric cylindrical shape. The planetary carrier  50  is arranged to extend from the radially inner side of the planetary rotor  30  to the radially inner side of the journal part  14 . The planetary carrier  50  has an input unit  51  having a cylindrical surface coaxial with the rotors  10  and  20  and the control shaft  6 . The input unit  51  is formed on the inner circumference surface of the circumference wall part. The input unit  51  has a connection slot  52  fitted to the joint  53 , and the control shaft  6  is connected with the planetary carrier  50  through the joint  53 , such that the planetary carrier  50  can rotate integrally with the control shaft  6 . 
     As shown in  FIG. 1 , the planetary carrier  50  has a coaxial part  56  on the outer circumference surface of the circumference wall part. The coaxial part  56  has a cylindrical surface coaxial with the rotors  10  and  20 . The coaxial part  56  is coaxially fitted to the inner wheel  15   b  of the drive bearing  15  from the outer side, and supports the driving rotor  10  from the radially inner side (radial bearing). Under this situation, the planetary carrier  50  can rotate relative to the rotors  10  and  20 , while coaxially rotating. 
     As shown in  FIGS. 1-3 , the planetary carrier  50  has an eccentric part  54  on the outer circumference surface of the circumference wall part. The eccentric part  54  has a cylindrical surface eccentric to the rotors  10  and  20 . The eccentric part  54  is coaxially fitted to the inner wheel  36   b  of the planetary bearing  36  from the outer side, and supports the planetary rotor  30  from the radially inner side (radial bearing). Under this bearing state, the planetary carrier  50  causes the planetary movement of the planetary rotor  30  according to the relative rotation to the driving rotor  10 . At this time, the planetary rotor  30  rotating in the own circumferential direction revolves in the rotating direction of the planetary carrier  50  under a gear engagement state where engaged with the rotors  10  and  20  on the eccentric side. 
     One metal elastic component  60  is received in a concave portion  55  opened at two positions in the circumferential direction of the eccentric part  54 . The elastic component  60  is a board spring having approximately U-shape in the cross-section. The elastic component  60  is interposed between the inner wheel  36   b  of the planetary bearing  36  of the planetary rotor  30  and the concave portion  55 . The elastic component  60  is compressed in the radial direction of the planetary rotor  30 , and is elastically deformed, such that the restoring force is generated. 
     As shown in  FIGS. 2 and 3 , a base line L is assumed to extend straight along with the radial direction in which the planetary rotor  30  is eccentric to the rotors  10  and  20 . The elastic component  60  is arranged at symmetry positions about the base line L in an arbitrary range in the axial direction. As a result, as shown in  FIGS. 2 and 4 , the total of the restoring forces of the elastic components  60  generates a radial force Fe acting on the planetary rotor  30  on the eccentric side along the base line L, and a radial force Fo of acting on the planetary carrier  50  on the other side opposite from the eccentric side (hereafter referred to “the other side”) along the base line L. In this way, while each elastic component  60  is held in the concave portion  55  by the radial force Fo on the other side, the planetary rotor  30  is biased by the radial force Fe on the eccentric side, such that the engagement state of the rotors  10  and  20  can be maintained on the eccentric side. 
     The phase adjustment unit  8  controls the rotation phase between the driving rotor  10  and the driven rotor  20  according to the rotation state of the control shaft  6 , such that the valve timing can be controlled suitably for the operation situation of the internal-combustion engine. 
     Specifically, when the planetary carrier  50  does not carry out relative rotation to the rotor  10 , the control shaft  6  rotates at the same speed as the driving rotor  10 , and the planetary rotor  30  does not carry out planetary movement and rotates with the rotors  10  and  20 . As a result, the rotation phase is substantially the same, and the valve timing is maintained. 
     When the planetary carrier  50  carries out relative rotation in the retard direction to the rotor  10 , the control shaft  6  rotates at a low speed or in an opposite direction to the driving rotor  10 , and the driven rotor  20  will carry out relative rotation in the retard direction to the driving rotor  10  by planetary movement of the planetary rotor  30 . As a result, the rotation phase is retarded to retard the valve timing. 
     When the planetary carrier  50  carries out relative rotation in the advance direction to the rotor  10 , the control shaft  6  rotates at a speed higher than the driving rotor  10 , and the driven rotor  20  will carry out relative rotation in the advance direction to the driving rotor  10  by planetary movement of the planetary rotor  30 . As a result, the rotation phase is advanced to advance the valve timing. 
     Hereafter, correlation of the radial forces generated in the phase adjustment unit  8  is explained based on  FIG. 4 . 
     The radial force Fe acting to the eccentric side by the elastic component  60  is distributed to a radial force Fed in which the planetary rotor  30  presses the driving rotor  10  to the eccentric side, and a radial force Fes in which the planetary rotor  30  presses the driven rotor  20  to the eccentric side. The radial force Fed acts on the driving rotor  10  from the planetary rotor  30  through the engagement part Pbd of the gear parts  12  and  32 . The radial force Fes acts on the driven rotor  20  from the planetary rotor  30  through the engagement part Pbs of the gear parts  24  and  34 . 
     The radial force Fred in which the driving rotor  10  presses the planetary rotor  30  to the other side is generated as a reaction of the radial force Fed. The radial force Fres in which the driven rotor  20  presses the planetary rotor  30  to the other side is generated as a reaction of the radial force Fes. The radial force Fred acts on the planetary rotor  30  from the driving rotor  10  through the engagement part Pbd of the gear parts  12  and  32 . The radial force Fres acts on the planetary rotor  30  from the driven rotor  20  through the engagement part Pbs of the gear parts  24  and  34 . 
     The radial force Fo acting to the other side by the elastic component  60  acts on the driving rotor  10  to the other side through the planetary carrier  50 . As the result, the radial force Fo is distributed to a radial force Fod in which the driving rotor  10  presses the planetary rotor  30  to the other side, and a radial force Fos in which the driving rotor  10  presses the driven rotor  20  to the other side. The radial force Fod acts on the planetary rotor  30  from the driving rotor  10  through the engagement part Pbd of the gear parts  12  and  32 . The radial force Fos acts on the driven rotor  20  from the driving rotor  10  through the radial bearing part Pr of the circumference surfaces  13   a  and  20   a.    
     The radial force Frod in which the planetary rotor  30  presses the driving rotor  10  is generated as a reaction of the radial force Fod. The radial force Fros in which the driven rotor  20  presses the driving rotor  10  to the eccentric side is generated as a reaction of the radial force Fos. The radial force Frod acts on the driving rotor  10  from the planetary rotor  30  through the engagement part Pbd of the gear parts  12  and  32 . The radial force Fros acts on the driving rotor  10  from the driven rotor  20  through the radial bearing part Pr of the circumference surfaces  13   a  and  20   a.    
     The radial force Fes, Fos acting on the driven rotor  20  is supported with the camshaft  2  connected with the rotor  20 . Moreover, the radial force Fed, Frod and the radial force Fred, Fod are cancelled by each other, respectively acting on the driving rotor  10  and the planetary rotor  30  through the engagement part of the gear parts  12  and  32 . Furthermore, the axial center Cbs of the engagement part Pbs and the axial center Cr of the radial bearing part Pr (refer to  FIG. 1 ) are shifted from each other in the axial direction, to which the radial force Fres and the radial force Fros act respectively. Thus, the radial force Fres and the radial force Fros generate an inclination moment Mi to make the driving rotor  10  inclined counterclockwise of  FIG. 4  to the driven rotor  20 . 
     The driving rotor  10  is inclined by the inclination moment Mi, and the end surface  11   a  of the driving rotor  10  is in contact with the end surface  20   b  of the driven rotor  20  on the other side. Therefore, the driving rotor  10  is supported by the driven rotor  20  from the side adjacent to the camshaft  2  in the axial direction (thrust bearing), and the thrust bearing part Po can be defined. On the eccentric side, the end surface  18   a  of the driving rotor  10  is in contact with the end surface  20   c  of the driven rotor  20 , and the driving rotor  10  is supported by the driven rotor  20  from the opposite side of the camshaft  2  in the axial direction (thrust bearing), such that the thrust bearing part Pe can be defined. 
     That is, the thrust bearing part Pe of the driving rotor  10  by the driven rotor  20  on the eccentric side is defined by the contact between the end surface  18   a  of the projection part  18  projected in the axial direction from the driving rotor  10  and the driven rotor  20 . As a result, the thrust bearing part Pe of the driving rotor  10  by the driven rotor  20  on the eccentric side is located on the radially inner side of the thrust bearing part Po of the driving rotor  10  by the driven rotor  20  on the other side, according to the spatial relationship of the end surfaces  11   a  and  18   a.    
     In order to realize the inclination of the driving rotor  10  and the thrust bearing of the driven rotor  20 , in this embodiment, three kinds of inclination states S 1 , S 2 , S 3  of the rotor  10  are assumed as shown in  FIGS. 5-7 . An inclination angle θ 1  is defined in the inclination state S 1 . An inclination angle θ 2  is defined in the inclination state S 2 . An inclination angle θ 3  is defined in the inclination state S 3 . Further, physical quantities δ 1 , δ 2 , δ 3 , L 1 , L 2 , L 3  are defined for the inclination angles θ 1 , θ 2 , θ 3 . 
     As shown in  FIG. 5 , the driving rotor  10  in the first inclination state S 1  is supposed, in which the end surfaces  11   a  and  18   a  are in contact with the driven rotor  20  on the both sides in the axial direction. Under this case, the inclination angle θ 1  of the driving rotor  10  to the driven rotor  20  in the state S 1  is defined. The inclination angle θ 1  is approximately given by the following formula 1 using the physical quantity θ 1  and L 1 , in which θ 1  represents a difference (Da−T) in dimension between the axial distance Da and the axial thickness T. The axial distance Da is defined between the end surfaces  11   a ,  18   a  in the axial direction where the thrust bearing is carried out by the driven rotor  20  to the driving rotor  10 . The driven rotor  20  has the axial thickness T in the axial direction between the end surfaces  11   a ,  18   a . L 1  represents a radial distance between the thrust bearing part Pe of the driving rotor  10  by the driven rotor  20  on the eccentric side and the thrust bearing part Po of the driving rotor  10  by the driven rotor  20  on the other side, in the radial direction. That is, L 1  is defined as the sum (Rd 1   e +Rd 1   o ) of the radius Rd 1   e  of the thrust bearing part Pe on the eccentric side and the radius Rd 1   o  of the thrust bearing part Po on the other side.
 
θ1≈arc tan(δ1/ L 1)  (formula 1)
 
     As shown in  FIG. 6 , the driving rotor  10  in the second inclination state S 2  is supposed, in which the inner circumference surface  13   a  is in contact with the driven rotor  20  on the both sides in the radial direction. Under this case, the inclination angle θ 2  of the driving rotor  10  to the driven rotor  20  in the state S 2  is defined. The inclination angle θ 2  is approximately given by the following formula 2 using the physical quantity δ 2  and L 2 , in which δ 2  represents a difference (φd 2 −φs) in dimension between the diameter φd 2  and the diameter φs. The inner circumference surface  13   a  has the diameter φd 2  in which the radial bearing is carried out by the driven rotor  20  to the driving rotor  10 . The outer circumference surface  20   a  has the diameter φs in which the radial bearing is carried out between the driving rotor  10  and the driven rotor  20 . L 2  represents a bearing width of the radial bearing part Pr by the driven rotor  20  to the driving rotor  10  in the axial direction. That is, L 2  is defined as an axial length of the radial bearing part Pr of the circumference surfaces  13   a ,  20   a  overlapping with each other.
 
θ2≈arc tan(δ2/ L 2)  (formula 2)
 
     As shown in  FIG. 7 , the driving rotor  10  in the third inclination state S 3  is supposed, in which the inner circumference surface  13   b  is in contact with the camshaft  2  on the both sides in the radial direction. Under this case, the inclination angle θ 3  of the driving rotor  10  to the driven rotor  20  in the state S 3  is defined. The inclination angle θ 3  is approximately given by the following formula 3 using the physical quantity δ 3  and L 3 , in which  83  represents a difference (φd 3 −φc) in dimension between the diameter φd 3  and the diameter φc. The inner circumference surface  13   b  has the diameter φd 3  in which the radial bearing is carried out by the camshaft  2  to the driving rotor  10 . The outer circumference surface  2   a  has the diameter φc in which the radial bearing is carried out between the driving rotor  10  and the camshaft  2 . L 3  represents a bearing width of the radial bearing part Pc (refer to  FIG. 4  and  FIG. 7 ) by the camshaft  2  to the driving rotor  10  in the axial direction. That is, L 3  is defined as an axial length of the radial bearing part Pc of the circumference surfaces  13   b ,  2   a  overlapping with each other.
 
θ3≈arc tan(δ3/ L 3)  (formula 3)
 
     Under the above definitions, in this embodiment, the following formulas 4 and 5 are satisfied to restrict the second inclination state S 2  and the third inclination state S 3  while realizing the first inclination state S 1 . Therefore, the driving rotor  10  can maintain to be in contact with the driven rotor  20  on the both sides in the axial direction, prior to the contact with the driven rotor  20  and the camshaft  2  on the both sides in the radial direction. In this embodiment, the structure of the phase adjustment unit  8  is designed to satisfy both the formulas 6 and 7 defined from the formulas 4 and 5 and the formulas 1-3.
 
θ1&lt;θ2  (formula 4)
 
θ1&lt;θ3  (formula 5)
 
δ1/ L 1&lt;δ2/ L 2  (formula 6)
 
δ1/ L 1&lt;δ3/ L 3  (formula 7)
 
     The action and effect of the valve timing controller  1  are explained below. 
     The formulas 4 and 5 are satisfied in the valve timing controller  1 . That is, the inclination angle θ 1  in the first inclination state S 1  is smaller than the inclination angle θ 2  in the second inclination state S 2  and is smaller than the inclination angle θ 3  in the third inclination state S 3 , when the driving rotor  10  is inclined to the driven rotor  20  by the restoring force of the elastic component  60 . Among the three kinds of assumed inclination states S 1 , S 2 , S 3 , the first inclination state S 1  is realized in fact, and the second inclination state S 2  and the third inclination state S 3  are restricted. 
     This means that the driving rotor  10  can be maintained to be in contact with the driven rotor  20  on the both sides in the axial direction prior to the contact with the driven rotor  20  and the camshaft  2  on the both sides in the radial direction, against the restoring force of the elastic component  60 . Therefore, the driving rotor  10  can be restricted from moving to the driven rotor  20  in the axial direction on the both sides, and abnormal noise caused by the collision of the rotors  10  and  20  can be controlled to provide more silence. 
     Moreover, the inclination angle θ 1 , θ 2 , θ 3  can be approximately expressed by the formula 1, 2, 3, respectively, in the inclination state S 1 , S 2 , S 3 . The formulas 4 and 5 will also be satisfied when the formulas 6 and 7 are satisfied. That is, the inclination angle θ 1  in the first inclination state S 1  can be made smaller than any of the inclination angle θ 2  in the second inclination state S 2  and the inclination angle θ 3  in the third inclination state S 3  properly by adopting the structure satisfying the formulas 6 and 7. Therefore, since the driving rotor  10  can be restricted from moving in the axial direction on the both sides according to the valve timing controller  1  having the structure satisfying the formulas 6 and 7, the noise caused by the collision of the rotors  10  and  20  can be restricted with more reliability. 
     Furthermore, the axial center Cr of the radial bearing part Pr of the driving rotor  10  by the driven rotor  20  and the axial center Cbs of the engagement part Pbs of the planetary rotor  30  to the driven rotor  20  are shifted from each other in the axial direction. In this case, it becomes easy to generate the inclination moment Mi which makes the driving rotor  10  inclined to the driven rotor  20  by the restoring force of the elastic component  60 . Accordingly, the driving rotor  10  inclined by the inclination moment Mi can be maintained certainly in the first inclination state S 1  where the driving rotor  10  is in contact with the driven rotor  20  on the both sides in the axial direction. Therefore, the noise caused by the collision of the rotors  10  and  20  can be restricted with more reliability. 
     Furthermore, the thrust bearing part Pe of the driving rotor  10  by the driven rotor  20  on the eccentric side is located on the radially inner side of the thrust bearing part Po of the driving rotor  10  by the driven rotor  20  on the other side. The thrust bearing part Pe on the eccentric side is defined by the contact between the driven rotor  20  and the projection part  18  projected in the axial direction from the driving rotor  10 . Thereby, since a space  17  (refer to  FIG. 1  and  FIG. 4 ) which permits the inclination of the driving rotor  10  can be formed on the radially outer side of the projection part  18 , it is easier to realize the first inclination state S 1  of the driving rotor  10  in contact with the driven rotor  20  on both sides in the axial direction. Therefore, the noise caused by the collision of the rotors  10  and  20  can be restricted with more reliability. 
     Modifications of the embodiment are described. 
     The axial center Cr of the radial bearing part Pr and the axial center Cbs of the engagement part Pbs may overlap with each other in the radial direction, while the formula 4 and the formula 5 are satisfied and the driving rotor  10  is inclined to the driven rotor  20  by the restoring force of the elastic component  60 . 
     The thrust bearing part Pe on the eccentric side may be located on the radially outer side of the thrust bearing part Po on the other side opposite from the eccentric side, while the formula 4 and the formula 5 are satisfied and the driving rotor  10  is inclined to the driven rotor  20  by the restoring force of the elastic component  60 . 
     As shown in  FIG. 8 , the driven rotor  20  may have a projection part  18  projected from an outer end surface  20   c  of the bottom wall part toward the camshaft in the axial direction. The thrust bearing part Pe on the eccentric side may be defined by a tip end surface  18   a  of the projection part  18  in contact with the inner bottom surface of the bottom wall part of the sprocket  13 . 
     One elastic component  60 , or three or more elastic components  60  may be arranged at a proper position between the planetary rotor  30  and the planetary carrier  50  while the restoring force is generated to bias the planetary rotor  30  to the eccentric side. 
     The present disclosure may be applied to the other equipment which adjusts the valve timing of an exhaust valve or adjusts the valve timing of both of the intake valve and the exhaust valve. 
     Such changes and modifications are to be understood as being within the scope of the present disclosure as defined by the appended claims.