Abstract:
A hydraulic orifice which is mounted at a head oil journal formed in a cylinder head and supplies an oil to a supply line after reducing pulsation of the oil supplied to the head oil journal, may include a body pressed on the head oil journal so as to form a chamber with the cylinder head, a joining line formed along a longitudinal axis of the body therein and fluid-communicating with the supply line, and at least two hydraulic lines formed in the body and connecting the chamber with an end of the joining line in the body to supply the oil through the other end thereof to the supply line, wherein the oils passing through the at least two hydraulic lines are joined at the end of the joining line with different phases such that the pulsation of the oil in the joining line is reduced.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     The present application claims priority to Korean Patent Application No. 10-2010-0086675 filed in the Korean Intellectual Property Office on Sep. 3, 2010, 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 hydraulic orifice, and more particularly to a hydraulic orifice which reduces pulsation of an oil supplied to a variable valve apparatus of an engine. 
     2. Description of Related Art 
     Generally, oil pressurized at a hydraulic pump passes through a hydraulic line in a cylinder block and is supplied to a cylinder head. Finally, the oil is supplied to various variable valve apparatuses through an oil control valve. 
     A head oil journal is formed between the cylinder block and the cylinder head of the engine, and a hydraulic orifice is mounted at the head oil journal such that a flow direction, a pressure, and a pulsation of the oil received from the hydraulic pump are controlled and the controlled oil is supplied to the oil control valve. 
     A conventional hydraulic orifice is mounted at a head oil journal formed in a cylinder head, and supplies oil received from a hydraulic pump to a supply line. 
     The hydraulic orifice includes an outer case and an inner case, the outer case is pressed on the head oil journal, and the inner case is pressed on an interior circumference of the outer case. At this time, a forming portion formed at the outer case is bent toward the inner case so as to assemble the inner case to the outer case. 
     An inner chamber is formed in the inner case. In addition, an oil hydraulic line for connecting the inner chamber with the supply line is formed at an exterior circumference of the inner case. The oil hydraulic line has spiral shape. 
     According to a conventional hydraulic orifice, however, pulsation of the oil is reduced when passing through the oil hydraulic line. Therefore, the oil hydraulic line having suitable length should be formed. For this purpose, the oil hydraulic line of spiral shape should be formed and it may be difficult to form the oil hydraulic line. 
     In addition, since the outer case and the inner case are assembled by bending the forming portion formed at the outer case toward the inner case, a diameter difference between both ends of the outer case cannot be controlled within a predetermined error range. Since the oil hydraulic line is formed at the exterior circumference of the inner case, a part of the oil hydraulic line may be blocked when the forming portion is bent. 
     Further, when pressing the outer case on the head oil journal, an oil passage flowing the oil received from the hydraulic pump into the cylinder head and a supply hole of the outer case should be aligned. For this purpose, an additional tool should be necessary and it may be hard to assemble. 
     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 hydraulic orifice having advantages of reducing pulsation as a consequence that a joining line and at least two hydraulic lines connecting the joining line with a head oil journal are formed at a body of one piece, and oils passing through at least two hydraulic lines are joined at the joining line with different phases and to provide a hydraulic orifice which has a simple structure by using the head oil journal as a chamber. Therefore, the hydraulic orifice can be easily assembled and manufacturing cost may be reduced. 
     In an aspect of the present invention, the hydraulic orifice which may be mounted at a head oil journal formed in a cylinder head and supplies an oil to a supply line after reducing pulsation of the oil supplied to the head oil journal may include a body pressed on the head oil journal so as to form a chamber with the cylinder head, a joining line formed along a longitudinal axis of the body therein and fluid-communicating with the supply line, and at least two hydraulic lines formed in the body and connecting the chamber with an end of the joining line in the body to supply the oil through the other end thereof to the supply line, wherein the oils passing through the at least two hydraulic lines may be joined at the end of the joining line with different phases such that the pulsation of the oil in the joining line may be reduced. 
     The at least two hydraulic lines may have different lengths such that the oils passing through the at least two hydraulic lines may be joined at the end of the joining line with the different phases. 
     The end of the joining line may be wider than the other end thereof to form a conical shape. 
     The head oil journal abuts on the supply line, and a diameter of the head oil journal may be larger than that of the supply line, and an end of the body may be pressed on the head oil journal and the other end of the body may be pressed on the supply line such that the chamber may be formed between the end of the body and the head oil journal. 
     The head oil journal abuts on the supply line, and a diameter of the head oil journal may be larger than that of the supply line, and wherein a diameter of both ends of the body may be larger than that of a middle portion of the body and the both ends of the body may be pressed on the head oil journal such that the chamber may be formed between the both ends of the body and the head oil journal. 
     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 schematic diagram showing that a hydraulic orifice according to an exemplary embodiment of the present invention is mounted at a head oil journal. 
         FIG. 2  is a perspective view of a hydraulic orifice according to an exemplary embodiment of the present invention. 
         FIG. 3  is a cross-sectional view of a hydraulic orifice according to an exemplary embodiment of the present invention. 
         FIG. 4  is another cross-sectional view of a hydraulic orifice according to an exemplary embodiment of the present invention. 
         FIG. 5  is a schematic diagram showing pulsations of oils passing through each hydraulic line formed at a hydraulic orifice according to an exemplary embodiment of the present invention. 
         FIG. 6  is a perspective view of a hydraulic orifice according to another exemplary embodiment of 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. 
       FIG. 1  to  FIG. 4  show a hydraulic orifice according to an exemplary embodiment of the present invention. 
     As shown in  FIG. 1  to  FIG. 4 , a hydraulic orifice  10  according to an exemplary embodiment of the present invention is mounted at a head oil journal  3  formed in a cylinder head  1 , and supplies oil received from a hydraulic pump to a supply line  5 . The oil in the supply line  5  is finally supplied to various variable valve apparatuses through an oil control valve. 
     The head oil journal  3  is formed at a coupling portion of the cylinder head  1  and a cylinder block, and the supply line  5  abuts on the head oil journal  3 . In addition, a diameter D 1  of the head oil journal  3  is larger than that D 2  of the supply line  5 . 
     The hydraulic orifice  10  includes a body  14  of one piece. The body  14  has circular cylinder shape. According to the first exemplary embodiment of the present invention, a diameter of one end  12  of the body  14  is larger than that of the other end of the body  14 . That is, the body  14  has ‘T’ shape. The one end  12  of the body  14  is pressed on an interior circumference of the head oil journal  3 , and the other end of the body  14  is pressed on the supply line  5 . Therefore, a chamber is formed between the one end  12  of the body  14  and the head oil journal  3 . For this purpose, the diameter of the one end  12  of the body  14  is almost the same as that D 1  of the head oil journal  3 , and the diameter of the other end of the body  14  is almost the same as that D 2  of the supply line  5 . In addition, a chamfer portion  22  may be formed at an exterior circumference of the other end of the body  14  such that the body  14  is easily pressed on the supply line  5 . 
     The chamber receives the oil from the hydraulic pump. 
     First and second hydraulic lines  16  and  18  and a joining line  20  are formed in the body  14 . 
     The first and second hydraulic lines  16  and  18  are formed from the exterior circumference of the body  14  to an inside of the body  14 . More concretely, one ends of the first and second hydraulic lines  16  and  18  are formed at the exterior circumference of the middle portion of the body  14  so as to communicate with the chamber, and the other ends of the first and second hydraulic lines  16  and  18  are joined in the body  14 . Therefore, the oil of the chamber flows through the first and second hydraulic lines  16  and  18 . 
     The joining line  20  is formed in the body  14  and extends toward the supply line  5 . More concretely, one end of the joining line  20  is connected to the other ends of the first and second hydraulic lines  16  and  18 , and the other end of the joining line  20  extends to the other end of the body  14  so as to be connected to the supply line  5 . Therefore, the oils passing through the first and second hydraulic lines  16  and  18  are joined at the joining line  20  and are supplied to the supply line  5  through the joining line  20 . 
     In addition, when the oils passing through the first and second hydraulic lines  16  and  18  are joined at the joining line  20 , pulsations of the oils are reduced. For this purpose, lengths of the first and second hydraulic lines  16  and  18  are different from each other. 
     In another exemplary embodiment of the present invention, the end of the joining line is wider than the other end thereof to form a conical shape. In this configuration, the oil pulsation will be further reduced while the oil passes through the joining line  20 . 
     Reduction of oil pulsation will be described referring to  FIG. 5 . 
       FIG. 5  is a schematic diagram showing pulsations of oils passing through each hydraulic line formed at a hydraulic orifice according to an exemplary embodiment of the present invention. 
     In  FIG. 5 , an oil flow in the chamber is denoted by X, and an oil flow in the joining line  20  is denoted by Y. In addition, an oil flow in the first hydraulic line  16  is called a first oil flow X 1 , and an oil flow in the second hydraulic line  18  is called a second oil flow X 2 . 
     If the oil flow X having a pulsation with a constant cycle is flowed in the chamber, the oil is input respectively to the first and second hydraulic lines  16  and  18 . At this time, cycle of the pulsation of the first oil flow X 1  is the same as that of the pulsation of the second oil flow X 2 . 
     If the length of the first hydraulic line  16  is the same as that of the second hydraulic line  18 , the first oil flow X 1  joins the second oil flow X 2  with the same phase, and the pulsation of the oil flow Y in the joining line  20  is not reduced from the pulsation of the oil flow X in the chamber. 
     If the length of the first hydraulic line  16  is different from that of the second hydraulic line  18 , the first oil flow X 1  and the second oil flow X 2  are joined with different phases, and the pulsation of the oil flow Y in the joining line  20  may be reduced from that of the oil flow X in the chamber. As shown in  FIG. 5 , if the first oil flow X 1  and the second oil flow X 2  are joined with a phase difference of 180°, the pulsation of the oil flow Y in the joining line  20  vanishes. 
     For this purpose, if wavelength of the pulsation is λ, a difference between the lengths of the first and second hydraulic lines  16  and  18  may be (2n+1)*λ. Herein, n is integer. 
     Meanwhile, if the length the first hydraulic line  16  is different from that of the second hydraulic line  18 , the pulsation of the oil in the joining line  20  may be reduced. If the lengths of the first and second hydraulic lines  16  and  18  are different from each other, the first oil flow X 1  and the second oil flow X 2  reaching the joining line  20  have different phases with each other. Therefore, the pulsation of the oil flow Y in the joining line  20  may be removed (even if the first oil flow and the second oil flow are joined with the same phase, the pulsation of the oil flow Y in the joining line  20  is the same as that of the oil flow X in the chamber, not be increased.). 
     So as to reduce the pulsation of the oil, means for changing phase of the oil may be mounted at one of the first and second hydraulic lines  16  and  18  instead of controlling the lengths of the first and second hydraulic lines  16  and  18 . For example, a penetration membrane with different refractive index may be mounted at one of the first and second hydraulic lines  16  and  18  so as to change the phase of the oil when the oil passes through the penetration membrane. 
       FIG. 6  is a perspective view of a hydraulic orifice according to another exemplary embodiment of the present invention. For better comprehension and ease of description, the same constituent elements will be denoted by the same reference numerals. 
     A hydraulic orifice  10 ′ according to the second exemplary embodiment of the present invention is the same as that  10  according to the first exemplary embodiment of the present invention except shape of the other end of the hydraulic orifice  10 . According to the second exemplary embodiment of the present invention, one end  12  of the body  14  has the same diameter as the other end  24  of the body  14 . Therefore, the other end  24  of the body  14  is pressed not on the supply line  5  but on the head oil journal  3 , and the chamber is formed between the both ends  12  and  24  of the body and the head oil journal  3 . 
     Operation of the second exemplary embodiment of the present invention is the same as that of the first exemplary embodiment of the present invention, and detailed description thereof will be omitted. 
     Meanwhile, it is exemplified in the exemplary embodiments of the present invention that two hydraulic lines  16  and  18  are used for supplying the oil in the chamber to the joining line  20 , but the number of the hydraulic lines is not limited to this. That is, at least two hydraulic lines may be used for supplying the oil in the chamber to the joining line  20 . In addition, at least two hydraulic lines have different lengths to each other. 
     As described above, since a joining line and at least two hydraulic lines connecting the joining line with a head oil journal are formed at a body of one piece and oils passing through at least two hydraulic lines are joined at the joining line with different phases, pulsation of the oil may be reduced according to the present invention. 
     In addition, since the head oil journal is used as a chamber, a structure may be simple. In addition, the hydraulic orifice can be easily assembled and manufacturing cost may be reduced. 
     For convenience in explanation and accurate definition in the appended claims, the terms “upper”, “lower”, “inner” and “outer” 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.