Abstract:
A variable valve lift device equipped with a swing arm variably lifting an exhaust valve or an intake valve may include an outer body in which a mounting groove is formed in the middle portion thereof, an inner body mounted inside the mounting groove of the outer body and with a rear end thereof pivotally-connected to the outer body in the outer body, and a latching portion formed in the outer body and the inner body and fixing or releasing a front end portion of the inner body to the outer body.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2009-0049638 filed on Jun. 4, 2009, the entire contents of which is incorporated herein for all purposes by this reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to a variable valve lift apparatus. More particularly, the present invention relates to a variable valve lift apparatus equipped with a swing arm that can variably adjust a lift amount of a valve depending on an operating condition of an engine. 
     2. Description of Related Art 
     An internal combustion engine generates power by burning fuel in a combustion chamber in an air media that is drawn into the chamber. 
     Intake valves are operated by a camshaft in order to intake the air, and the air is drawn into the combustion chamber while the intake valves are open. In addition, exhaust valves are operated by the camshaft, and a combustion gas is exhausted from the combustion chamber while the exhaust valves are open. 
     An optimal operation of the intake valves and the exhaust valves depends on a rotation speed of the engine. That is, an optimal lift or optimal opening/closing timing of the valves depends on the rotation speed of the engine. 
     For example, research has been undertaken for a variable valve lift (VVL) apparatus that enables different lifts depending on engine speed, and for a variable valve timing (VVT) apparatus that opens/closes the valves with different timing depending on the engine speed. 
     The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art. 
     BRIEF SUMMARY OF THE INVENTION 
     Various aspects of the present invention are directed to provide a variable valve lift apparatus having advantages of varying a lift amount of a valve according to a driving condition of an engine. 
     The variable valve lift device is equipped with a swing arm variably lifting an exhaust valve or an intake valve, wherein the swing arm may include an outer body in which a mounting groove is formed in the middle portion thereof, an inner body mounted inside the mounting groove of the outer body and with a rear end thereof pivotally-connected to the outer body in the outer body, and a latching portion formed in the outer body and the inner body and fixing or releasing a front end portion of the inner body to the outer body. 
     The rear end of the inner body and the outer body may be pivotally connected with each other by a lost motion elastic member so that the inner body is elastically biased toward the outer body. 
     A front end surface of the inner body may be disposed to slide with an inner side surface of the mounting groove while the front end portion of the inner body is released from the outer body by the latching portion such that the inner body rotates based on the hinge. 
     The front end surface of the inner body and the inner side surface of the mounting groove of the outer body may be formed along a circle based on the center of a hinge coupling the rear end of the inner body and the outer body and has substantially the same curvature. 
     The latching portion may include an elastic member inserted into a spring groove formed in the front end portion of the inner body, a guide slidably disposed at a front end portion of the elastic member in the spring groove to be elastically moved by the elastic member toward the inner side surface of the mounting groove, a latching pin slidably inserted into a pin groove formed in the inner side surface of the mounting groove, wherein the pin groove is positioned to correspond to the spring groove when the inner body and the outer body is coupled, and a hydraulic pressure supply portion supplying hydraulic pressure to an inner side of the pin groove to insert a front end portion of the latching pin into the spring groove. 
     The variable valve lift device may further include a control portion that controls the hydraulic pressure supply portion according to a driving condition, wherein the front end portion of the latching pin pushes the guide to be inserted into the spring groove such that the inner body and the outer body are coupled to move together according to the hydraulic pressure, and wherein the latching pin is elastically drawn out from the spring groove by the elastic member such that the inner body is decoupled from the outer body to rotate based on a hinge coupling the rear end of the inner body and the outer body and when the hydraulic pressure is released. 
     The variable valve lift device may further include a roller disposed on the inner body and spaced with a predetermined distance from the rear end of the inner body to contact a cam, a hydraulic pressure gap adjustment device supporting one end portion of the outer body, and a valve supporting the other end portion of the outer body to open or close an air passage according to the movement of the outer body. 
     The hydraulic pressure may be supplied to the pin groove through an oil passage formed in the one end portion of the outer body and connected to the hydraulic pressure gap adjustment device. 
     In another aspect of the present invention, the variable valve lift apparatus, may include an outer body in which a mounting groove is formed in the middle portion thereof, an inner body that is mounted in the mounting groove of the outer body and a front end surface thereof slides with an inner side surface of the mounting groove of the outer body, wherein a rear end portion of the inner body is pivotally connected to the outer body by a hinge, and a latching portion formed in the outer body and the inner body and selectively coupling a front end portion of the inner body to the outer body, wherein the latching portion includes: an elastic member inserted into a spring groove formed in the front end portion of the inner body, a guide slidably disposed at a front end portion of the elastic member in the spring groove, and a latching pin slidably inserted into a pin groove formed in the inner side surface of the mounting groove, wherein the pin groove is positioned to correspond to the spring groove when the inner body and the outer body is coupled. 
     A stopper may be formed such that the guide does not protrude out of the front end surface of the inner body. 
     The stopper may include a protrusion formed on an interior circumference of the spring groove and prevents the guide from protruding out of the spring groove, wherein a groove is formed on an exterior circumference of the guide corresponding to the protrusion and the protrusion slides therein. 
     The stopper may include a protrusion formed on an interior circumference of the pin groove and prevents the guide from protruding out of the spring groove of the inner body, wherein a groove is formed on an exterior circumference of the latching pin corresponding to the protrusion and the protrusion slides therein. 
     The variable valve lift apparatus may include a lost motion elastic member that is disposed on the hinge to couple the inner body and the outer body and elastically bias the inner body toward the outer body based on the hinge. 
     The variable valve lift apparatus may further include a hydraulic pressure supply portion that supplies hydraulic pressure into the pin groove so as to push the latching pin forward. 
     The front end surface of the inner body and the inner side surface of the mounting groove may contact to slide with each other. 
     As stated above, in the variable valve lift apparatus equipped with a swing arm according to an exemplary embodiment of the present invention, a swing arm is divided into the inner body and the outer body, and the latching device connects or separates them such that the valve is variably controlled. Accordingly, the combustion cylinder can be efficiently deactivated according to a driving condition of an engine. 
     The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description of the Invention, which together serve to explain certain principles of the present invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a partial perspective view of an exemplary variable valve lift apparatus equipped with a swing arm according to the present invention. 
         FIG. 2  is a partial cross-sectional view of an exemplary variable valve lift apparatus equipped with a swing arm in a condition in which hydraulic pressure is supplied according to the present invention. 
         FIG. 3  is a partial cross-sectional view of an exemplary variable valve lift apparatus equipped with a swing arm in a condition in which hydraulic pressure is not supplied according to the present invention. 
         FIG. 4  is a partial exploded side view of an exemplary variable valve lift apparatus equipped with a swing arm according to the present invention. 
         FIG. 5(A)  and  FIG. 5(B)  are a partial detail side view of an exemplary variable valve lift apparatus equipped with a swing arm according to the present invention. 
     
    
    
     It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment. 
     In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims. 
     An exemplary embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings. 
       FIG. 1  is a partial perspective view of a variable valve lift apparatus equipped with a swing arm according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 1 , a variable valve lift apparatus includes a swing arm  100 , and the swing arm  100  includes an outer body  105   a , an inner body  105   b , a roller  120 , a hinge  115 , and a lost motion spring  110 . 
     A right lower surface of the outer body  105   a  is supported by a hydraulic pressure gap adjustment device  130 , a left lower surface thereof contacts an upper end of a valve  140 , and the hydraulic pressure gap adjustment device  130  receives hydraulic pressure from a hydraulic pressure supply portion  150  to support one side of the outer body of the swing arm  100 . The hydraulic pressure supply portion supplies the hydraulic pressure according to a control signal of a control portion (not shown). 
     The inner body  105   b  is mounted in an inner side mounting groove  204  of the outer body  105   a  of  FIG. 2 , a front end portion of the inner body  105   b  faces the hydraulic pressure gap adjustment device  130 , and a rear end portion thereof faces the valve  140 . 
     The rear end portion of the inner body  105   b  is connected to the outer body  105   a  by the hinge  115 , and the lost motion spring  110  is disposed on the hinge  115  to elastically rotate the inner body  105   b  in a counterclockwise direction based on the hinge  115 . 
     The roller  120  is disposed in the middle portion of the inner body  105   b  to protrude in an upper direction, and if the roller  120  is pushed in a lower direction by a cam  205  of  FIG. 2 , the swing arm  100  moves the valve  140  down. 
     A latching structure is used to move or not to move the valve  140  in an exemplary embodiment of the present invention, and detail structures will be explained referring to  FIG. 2  and  FIG. 3 . 
       FIG. 2  is a partial cross-sectional view of a variable valve lift apparatus equipped with a swing arm in a condition in which hydraulic pressure is supplied according to an exemplary embodiment of the present invention, and  FIG. 3  is a partial cross-sectional view of a variable valve lift apparatus equipped with a swing arm in a condition in which hydraulic pressure is not supplied according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 2  and  FIG. 3 , the mounting groove  204  that is opened from an upper surface to a lower surface is formed in the middle of the outer body  105   a , and the inner body  105   b  is disposed right and left in the mounting groove  204 . 
     A left end portion, that is, a rear end portion of the inner body  105   b , is fixed to the outer body  105   a  by the hinge  115 , and a right front end surface  304  slides with an inner side surface  302  of the mounting groove  204 . Also, the roller  120  is rotatably disposed on the middle portion of the inner body  105   b , the cam  205  is disposed at an upper side of the roller  120 , and the cam  205  contacts the roller  120 . 
     In the outer body  105   a , a cylindrical pin groove  202  is formed on the inner side surface that slides with the front end surface  304  of the inner body  105   b , and a latching pin  220  is inserted into the pin groove  202 . The pin groove  202  is opened to a side of the front end surface  304  of the inner body  105   b , and is connected to the hydraulic pressure gap adjustment device  130  and the hydraulic pressure supply portion  150  through an oil passage  215 . 
     In the inner body  105   b , a spring groove  203  is formed corresponding to the pin groove  202  on the front end surface  304  that slides with the inner side surface  302  of the outer body  105   a , a return spring  200  is inserted into the spring groove  203 , and a guide  210  is disposed at an end portion of the return spring  200 . Further, the spring groove  203  is opened to a side of the inner side surface  302  of the outer body  105   a.    
     In an exemplary embodiment of the present invention, the front end surface  304  of the outer body  105   a  and the inner side surface  302  of the inner body  105   b  are formed along a circle based on the center of the hinge  115 . 
     A function of a latching pin connecting or separating the inner body  105   b  and the outer body  105   a  is explained as follows. If the hydraulic pressure is supplied into the pin groove  202  through the hydraulic pressure gap adjustment device  130 , the front end portion of the latching pin  220  is inserted into the spring groove  203 . 
     Accordingly, the latching pin  220  is disposed along the spring groove  203  and the pin groove  202 , and if the cam  205  pushes the roller  120  downwards, the inner body  105   b  and the outer body  105   a  rotate based on the hydraulic pressure gap adjustment device  130  to push the valve  140  downwards. 
     Further, if the hydraulic pressure is not supplied to the pin groove  202  through the hydraulic pressure gap adjustment device  130 , the guide  210  pushes the latching pin  220  by the return spring  200  such that the latching pin  220  is inserted into the pin groove  202  and the inner body  105   b  and the outer body  105   a  are separated, and if the cam  205  pushes the roller  120  downwards, the inner body  105   b  rotates in a clockwise based on the hinge  115  such that the outer body  105   a  does not move. Accordingly, the valve  140  does not move, and an intake stroke, a compression stroke, an explosion stroke, or an exhaust stroke is deactivated. 
     It is desirable that the front end surface  304  of the inner body  105   b  and the inner side surface  302  of the outer body  105   a  contact to slide with regard to each other in an exemplary embodiment of the present invention, and the front end surface  304  and the inner side surface  302  are formed in a fan shape along a circle based on a center of the hinge  115 . 
     Further, in a case that the hydraulic pressure is not be supplied into the pin groove  202 , a stopper is formed in the outer body or the inner body such that the guide  210  does not protrude outside the front end surface  304 . The stopper can be a protrusion that is formed on an interior circumference of the spring groove  203  or on an interior circumference of the pin groove  202 . 
       FIG. 4  is a partial exploded side view of a variable valve lift apparatus equipped with a swing arm according to an exemplary embodiment of the present invention, and  FIG. 5(A)  and  FIG. 5(B)  are a partial detail side view of a variable valve lift apparatus equipped with a swing arm according to an exemplary embodiment of the present invention. 
     Referring to  FIG. 4 , the return spring  200  is a coil spring type, and the guide  210  is a circular cup type to cover the front end of the return spring  200 . Further, the latching pin  220  is a cylindrical type, a front surface of the guide  210  is formed in a fan shape along the front end surface  304  of the inner body  105   b , and a front surface of the latching pin  220  is formed in a fan shape along the inner side surface  302 . 
     Referring to  FIG. 4  and  FIG. 5(A) , a protrusion  500  is formed on an interior circumference of the pin groove  202  of the outer body  105   a , and the protrusion  500  is disposed in a movement direction of the inner body  105   b . Further, a groove  400  is formed on an exterior circumference of the latching pin  220  corresponding to the protrusion  500 , and the groove  400  guides the movement of the latching pin  220  in a length direction thereof. 
     Referring to  FIG. 5(A) , the protrusion  500  is disposed in a position that is inserted from the inlet of the pin groove  202  with a predetermined length, and the groove  400  is formed at an exterior circumference of the latching pin  220  in a length direction and is not formed at a front portion of the latching pin  220  such that the front surface of the latching pin is not inserted into the pin groove  202 . 
     Referring to  FIG. 5(B) , the protrusion  600  may be disposed in a position that is inserted from the inlet of the spring groove  203  with a predetermined length, and the groove  700  is formed at an exterior circumference of the guide  210  in a length direction and is not formed at a rear portion of the guide  210  such that the front surface of the guide  210  does not protrude out of the spring groove  203 . 
     Accordingly, if the hydraulic pressure is not supplied, the latching pin  220  is not inserted into the spring groove  203  such that the guide  210  pushes the latching pin  220  by the elastic force of the return spring  200 , and the front end surface  304  of the inner body  105   b  smoothly slides with the inner side surface  302  of the outer body  105   a  without locking. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “front”, “rear”, “interior”, “exterior”, “outer”, and “inner” are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures. 
     The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.